The question is simple enough: Who had baseball's best fastball in 2021?

However, rather than simply looking at radar gun readings, I took a more analytical approach to compiling this list of the sport's best heaters.

The first step was to decide what combination of statistics most aptly quantifies "best."

After some digging and debating, I landed on these four:

• Usage Rate (Usage%): The percentage of time the pitch is thrown relative to a pitcher's full arsenal of offerings.
  
  
• Batting Average Against (BAA): Opposing hitters' batting average produced when facing the pitch.

• Isolated Power Against (ISO): Opposing hitters' extra bases per at-bat against fastballs. Calculated by taking slugging percentage allowed minus batting average allowed.

• Strikeout Total (K): Since counting stats should still mean something, each player's 2021 strikeout total was also part of the equation.

The question then became how to use those statistics to best demonstrate the difference between Player A and Player B in terms of fastball effectiveness.

Methodology

For those of you who read our Skill Rankings series last year, we've tweaked things quite a bit from the 2021 version.

The first step was to narrow the field, and 500 pitches thrown was used as the cutoff for a pitch to be considered for inclusion. That helped to eliminate small sample-size data skew.

The result was 206 fastballs eligible for consideration.

From there, a simple system was implemented that awarded points as follows:

• 1 point for every .001 below .140 in ISO, minus-1 point for every .001 above .140 in ISO
• 1 point for every .001 below .250 in BAA, minus-1 point for every .001 above .250 in BAA
• 2 points for every strikeout recorded in 2021 with the pitch

The resulting figure was then multiplied by each player's usage rate in an effort to further reward pitchers who lean more heavily on their fastball to succeed.

No bias. No preconceived notions. Just a set of statistical parameters and a straightforward point system to determine the current 25 best fastballs in baseball.

The full data can be found here.

Top 10 Sinkers

It's tough to quantify a sinker in the same way you do a traditional fastball, since the goal of a sinker is often to generate ground balls. As a result, sinkers were not included in our top 25 fastballs list, but here's a quick rundown of the best sinkers based on our scoring system:

• 1. Kendall Graveman, CWS (134.0 points)
• 2. Adrian Houser, MIL (125.4 points)
• 3. Clay Holmes, NYY (123.1 points)
• 4. Tim Mayza, TOR (121.4 points)
• 5. Ranger Suarez, PHI (108.3 points)
• 6. Sean Manaea, OAK (93.0 points)
• 7. Jonathan Loaisiga, NYY (85.6 points)
• 8. Adam Wainwright, STL (74.5 points)
• 9. Zach Pop, MIA (67.7 points)
• 10. Steven Matz, STL (57.1 points)

Nos. 25-21

25. LHP Genesis Cabrera, St. Louis Cardinals (93.4 points)

Pitch: Four-seam fastball

Metrics: 44.7 Usage%, 97.6 mph, .109 ISO, .164 BAA, 46 K

Cabrera made a career-high 71 appearances in 2021, leading the St. Louis Cardinals with 28 holds while posting a 3.73 ERA and 9.9 K/9 in 70 innings. The southpaw actually had reverse platoon splits, limiting right-handed hitters to a .178 average and .550 OPS with his full arsenal.

24. RHP Ian Kennedy, Free Agent (95.7 points)

Pitch: Four-seam fastball

Metrics: 82.5 Usage%, 94.1 mph, .165 ISO, .207 BAA, 49 K

Armed with a five-pitch repertoire during his time in the starting rotation, Kennedy simplified his approach since moving to the bullpen. He was essentially a one-pitch pitcher in 2021, mixing in the occasional changeup and curveball while pitching mostly off his mid-90s fastball en route to 26 saves.

23. RHP Gerrit Cole, New York Yankees (96.1 points)

Pitch: Four-seam fastball

Metrics: 47.1 Usage%, 97.7 mph, .173 ISO, .225 BAA, 106 K

Surprised? Cole threw his fastball less (minus-5.7 percentage points) and his changeup more (plus-8.6 points) relative to the 2020 season, and while his heater still has elite velocity and accounted for 106 strikeouts, the underlying metrics on the pitch were not quite as dominant as we've seen in years past.

22. RHP Brandon Woodruff, Milwaukee Brewers (97.1 points)

Pitch: Four-seam fastball

Metrics: 33.7 Usage%, 96.5 mph, .138 ISO, .190 BAA, 113 K

Woodruff throws a healthy mix of four-seam fastballs (33.7 Usage%) and sinkers (26.7 Usage%), with the two pitches serving very different purposes in his approach. The four-seamer is his go-to strikeout pitch, accounting for 113 of his 211 punchouts, and the lack of usage is the only reason it doesn't rank higher.

21. RHP Chad Green, New York Yankees (100.3 points)

Pitch: Four-seam fastball

Metrics: 65.1 Usage%, 95.7 mph, .179 ISO, .185 BAA, 64 K

One of baseball's most valuable relievers, Green tallied 10 wins, six saves and 18 holds while recording more than three outs in 26 of his 67 appearances. He can reach back for a little more when he needs it but sits comfortably in the mid-90s with a terrific breaking ball to keep hitters off balance.

Nos. 20-16

20. RHP Max Scherzer, New York Mets (100.9 points)

Pitch: Four-seam fastball

Metrics: 46.7 Usage%, 94.3 mph, .167 ISO, .193 BAA, 93 K

Scherzer's lively mid-90s fastball is made even better by the presence of a terrific slider/changeup pairing that keeps opponents on edge. Never afraid of challenging a hitter, he allowed 11 home runs on four-seam fastballs, which contributed to higher-than-most ISO.

19. RHP Brad Boxberger, Free Agent (101.2 points)

Pitch: Four-seam fastball

Metrics: 55.9 Usage%, 93.5 mph, .152 ISO, .181 BAA, 62 K

Boxberger pitched his way onto the Milwaukee Brewers roster on a minor league deal last spring, and he went on to post a 3.34 ERA and 11.6 K/9 with 23 holds in 71 appearances. The 33-year-old mixes pitches better than most relievers, throwing his slider and changeup each more than 20 percent of the time.

18. RHP Lance Lynn, Chicago White Sox (106.0 points)

Pitch: Four-seam fastball

Metrics: 40.3 Usage%, 94.0 mph, .110 ISO, .187 BAA, 85 K

Every offering is hard from Lynn, who works mostly off a four-seam fastball (94.0 mph, 40.3 Usage%), cutter (88.7 mph, 31.0%) and sinker (92.4 mph, 19.4%). His cutter checked in at No. 67 in these rankings, but it's his four-seamer that is the bread-and-butter of his power approach.

17. LHP Robbie Ray, Seattle Mariners (114.0 points)

Pitch: Four-seam fastball

Metrics: 59.4 Usage%, 94.8 mph, .208 ISO, .222 BAA, 116 K

No one threw more four-seam fastballs than the 1,866 that Ray delivered in 2021. The AL Cy Young winner leaned more heavily on the pitch than most starters, which inevitably led to more damage during a full season. His .208 ISO was the highest among the top 25, but the overall statistical package was elite.

16. Paul Sewald, Seattle Mariners (115.4 points)

Pitch: Four-seam fastball

Metrics: 58.3 Usage%, 92.3 mph, .140 ISO, .180 BAA, 64 K

Sewald had a 5.50 ERA in 125 career appearances entering 2021. The 31-year-old went 10-3 with 11 saves and 16 holds while posting a 3.06 ERA and 14.5 K/9 in 62 appearances after signing a minor league deal with Seattle. A more effective slider helped him unlock the full potential of his fastball.

Nos. 15-11

15. RHP Tyler Mahle, Cincinnati Reds (118.4 points)

Pitch: Four-seam fastball

Metrics: 53.1 Usage%, 94.0 mph, .199 ISO, .236 BAA, 134 K

Mahle led all pitchers with 134 strikeouts with his four-seam fastball, but he also surrendered 18 doubles and 16 home runs with the pitch for a .435 opponents' slugging percentage. His slider's effectiveness regressed while his fastball's improved, and putting it all together could make him an ace-caliber pitcher.

14. RHP Jacob deGrom, New York Mets (121.1 points)

Pitch: Four-seam fastball

Metrics: 57.4 Usage%, 99.2 mph, .145 ISO, .158 BAA, 62 K

Hear me out. The thing that kept deGrom out of the top 10 was the time he missed. Pitching only 92 innings prevented him from getting the same bump up the rankings that other starters received for their strikeout total. His slider is his best pitch, but his fastball will also be a top-10 offering again in 2022 if he can stay healthy.

13. LHP Blake Taylor, Houston Astros (121.8 points)

Pitch: Four-seam fastball

Metrics: 72.5 Usage%, 93.1 mph, .072 ISO, .216 BAA, 33 K

Of the 206 fastballs that qualified for inclusion in these rankings, Taylor had the third-lowest average exit velocity allowed at 82.8 mph. That helped contribute to the four-seamer's microscopic .072 ISO, as he allowed just one home run and six total extra-base hits with the pitch while throwing his heater 72.5 percent of the time.

12. RHP Jordan Romano, Toronto Blue Jays (122.5 points)

Pitch: Four-seam fastball

Metrics: 62.2 Usage%, 97.6 mph, .149 ISO, .140 BAA, 48 K

Romano has seen a steady uptick in both his fastball velocity and spin rate over the past three seasons, going from 94.6 mph and 2,261 RPM in 2019 to 97.6 mph and 2,390 RPM in 2021. That paved the way for a breakout season in 2021 as he posted a 2.14 ERA and 12.1 K/9 with 23 saves in 62 appearances.

11. RHP Kenley Jansen, Los Angeles Dodgers (125.3 points)

Pitch: Cutter

Metrics: 58.0 Usage%, 92.5 mph, .072 ISO, .176 BAA, 37 K

Just a few years ago, Jansen was still throwing his cutter more than 80 percent of the time. However, he has been forced to expand his repertoire, and he regularly mixed in sinkers (26.6 Usage%) and sliders (15.4 Usage%) in 2021. His cutter is still a dominant pitch; it just can't stand alone anymore.

10. RHP Emmanuel Clase, Cleveland Guardians (125.9 Points)

Pitch: Cutter

Metrics: 69.2 Usage%, 100.2 mph, .056 ISO, .236 BAA, 42 K

Emmanuel Clase lit up radar guns around the league throughout his rookie season, averaging 100.2 mph on his cutter, which also featured 2.7 inches of horizontal break.

That's simply not fair.

His .056 ISO was the lowest of any fastball that qualified for this list, and he surrendered just five extra-base hits on the 731 cutters he threw.

The 23-year-old finished with a 1.29 ERA, 0.96 WHIP and 9.6 K/9 in 71 appearances, converting 24 of 29 save chances to finish fifth in AL Rookie of the Year voting.

9. RHP Zack Wheeler, Philadelphia Phillies (126.4 Points)

Pitch: Four-seam fastball

Metrics: 42.4 Usage%, 97.2 mph, .092 ISO, .224 BAA, 112 K

One of baseball's hardest-throwing starters throughout his career, Zack Wheeler posted a career-high 97.2 mph velocity with his four-seam fastball in 2021.

The pitch accounted for 112 of his NL-leading 247 strikeouts, and a dominant slider helped turn his heater into a better put-away pitch as hitters were often left looking for his low-90s breaking ball and instead blown away by his fastball.

He surrendered just five home runs with his fastball while throwing the pitch 1,360 times.

8. LHP Tyler Matzek, Atlanta Braves (131.5 Points)

Pitch: Four-seam fastball

Metrics: 70.7 Usage%, 96.0 mph, .096 ISO, .192 BAA, 42 K

A starter at the onset of his big league career with the Colorado Rockies, Tyler Matzek went five years between appearances in the majors, resurfacing with the Atlanta Braves as a reliever in 2020.

In his final season as a starter in 2015, he threw more sliders than fastballs and averaged just 92.3 mph and 2,046 RPM with his four-seamer. After a brief tour of the independent league and some time in the minors, he has returned as a new pitcher, checking in at 96.0 mph and 2,435 RPM with his fastball in 2021.

The 31-year-old was an integral part of Atlanta's postseason run last year, posting a 1.72 ERA in 15.2 innings while tallying three wins and five holds in 13 appearances.

6 (tie). LHP Darwinzon Hernandez, Boston Red Sox (137.4 Points)

Pitch: Four-seam fastball

Metrics: 73.1 Usage%, 94.8 mph, .100 ISO, .182 BAA, 40 K

Despite a general lack of command and no viable secondary pitch, Darwinzon Hernandez has developed into a useful relief arm for the Boston Red Sox thanks to his plus fastball.

The 25-year-old danced around danger for much of the 2021 season, walking 31 batters in 40 innings and posting a 1.50 WHIP, yet he came away with a 3.38 ERA and 12 holds in 48 appearances in large part because of his ability to limit damage with his four-seamer.

Opponents hit .286 with a .607 slugging percentage against his slider, which he threw 20.6 percent of the time as his go-to breaking pitch. Improving that offering will be the key to unlocking the rest of his game.

6 (tie). LHP Carlos Rodon, Chicago White Sox (137.4 Points)

Pitch: Four-seam fastball

Metrics: 58.7 Usage%, 95.4 mph, .137 ISO, .199 BAA, 90 K

One of the biggest surprises of the 2021 season, Carlos Rodon finally lived up to the hype that came with being the No. 3 pick in the 2014 draft following a standout career at NC State.

Saddled with injuries throughout his career, he was nontendered by the Chicago White Sox at the start of last offseason, only to return on a one-year, $3 million deal to compete for the No. 5 starter job. He won the spot in the rotation, threw a no-hitter in his second start and finished with a 2.37 ERA, 0.96 WHIP and 185 strikeouts in 132.2 innings.

His slider was his best pitch, holding opponents to a .107 average and accounting for 91 of his 185 strikeouts, but his fastball was also elite. His 95.4 mph average velocity was a career high and represented an increase of nearly three ticks from his 92.8 mph velocity in 2020.

5. LHP Jake McGee, San Francisco Giants (139.7 Points)

Pitch: Four-seam fastball

Metrics: 90.1 Usage%, 94.9 mph, .139 ISO, .194 BAA, 49 K

No one featured their fastball in a higher percentage of their arsenal than Jake McGee in 2021.

The 35-year-old went to his four-seamer more than 90 percent of the time, essentially abandoning the slider he had featured prominently in years past.

Despite the predictability of his approach, he finished with a 2.72 ERA, 0.91 WHIP and a 58-to-10 strikeout-to-walk ratio in 59.2 innings. He nailed down 31 saves in 36 chances and helped the Giants post baseball's best bullpen ERA.

His two-year, $5 million contract has already been an absolute steal.

4. LHP Trevor Rogers, Miami Marlins (140.8 Points)

Pitch: Four-seam fastball

Metrics: 57.7 Usage%, 94.5 mph, .122 ISO, .222 BAA, 99 K

After scuffling to a 6.11 ERA in seven starts in 2020, Trevor Rogers broke out as one of baseball's best young pitchers last season.

The 24-year-old posted a 2.64 ERA, 1.15 WHIP and 157 strikeouts in 133 innings to finish runner-up to Jonathan India in NL Rookie of the Year voting, and he earned a spot on the NL All-Star team thanks to a brilliant first half.

His fastball plays up thanks to a lethal changeup that held opposing hitters to a .199 average and .265 slugging percentage while inducing a 33.7 percent whiff rate. Don't be surprised if that one also makes an appearance in our rundown of the best off-speed pitches in baseball.

3. RHP Corbin Burnes, Milwaukee Brewers (154.8 Points)

Pitch: Cutter

Metrics: 52.3 Usage%, 95.2 mph, .091 ISO, .237 BAA, 117 K

Corbin Burnes threw five different pitches more than 200 times during the 2021 season.

He used his changeup almost exclusively against left-handed hitters and his slider nearly exclusively against right-handed hitters, while his cutter and curveball were his bread-and-butter regardless of who was standing in the batter's box.

The curveball is statistically his most dominant pitch, but it's the development of his cutter that has taken him from promising young pitcher to Cy Young winner. He threw the pitch just eight times in 2019 and still leaned more heavily on his sinker in 2020, but everything centered around that cutter last season, and the results speak for themselves.

The 27-year-old led the majors with a 2.43 ERA while posting a staggering 234-to-34 strikeout-to-walk ratio in 167 innings to edge Wheeler and Scherzer for NL Cy Young honors.

2. RHP Freddy Peralta, Milwaukee Brewers (155.8 Points)

Pitch: Four-seam fastball

Metrics: 51.6 Usage%, 93.4 mph, .152 ISO, .156 BAA, 110 K

Among all pitchers with at least 100 innings in 2021, Freddy Peralta led the way with a .156 opponents' batting average.

The 25-year-old was baseball's best No. 3 starter, going 10-5 with a 2.81 ERA, 0.97 WHIP and 195 strikeouts in 144.1 innings while pitching behind Burnes and Woodruff in the Milwaukee Brewers rotation, but he has the best fastball of the trio.

An increase in slider usage (plus-21.6 percentage points) to match a decrease in fastball usage (minus-21.9 points) ultimately made his fastball more effective, as a more balanced approach kept hitters from sitting on his four-seamer.

That five-year, $15.5 million extension he signed prior to the 2020 season (and its two additional club-option years) suddenly looks like one of the best contracts in baseball.

1. LHP Josh Hader, Milwaukee Brewers (224.7 Points)

Pitch: Four-seam fastball

Metrics: 65.5 Usage%, 96.4 mph, .068 ISO, .103 BAA, 62 K

There are a lot of great fastballs on this list, and Josh Hader came out on top by a landslide.

Baseball's most dominant relief pitcher threw his fastball roughly two-thirds of the time last season, and he limited opponents to a .103 batting average, the lowest mark among pitchers who threw at least 500 fastballs in 2021.

The 27-year-old was equally effective against right-handed hitters (.125 BA, .434 OPS) and left-handed hitters (.133 BA, .376 OPS) overall, and he surrendered just two home runs and four total extra-base hits on the 631 fastballs he threw.

He struck out 102 of the 224 batters he faced, posting a 1.23 ERA, 0.84 WHIP and 15.6 K/9 while converting 34 of 35 save chances in 60 appearances.

All stats courtesy of Baseball Reference and Baseball Savant.