In recent weeks, MLB coverage has shifted to a more nostalgic tone as the sports world reminisces amid an uncertain future.

While digging into the past 20 years of baseball history, I've come across more than a few forgotten league leaders.

Remember when Boston Red Sox third baseman Bill Mueller won the AL batting title?

What about when 2006 AL MVP Justin Morneau won the NL batting crown during his brief stint with the Colorado Rockies?

Ahead we've chosen the 10 most surprising league leaders of the past 20 years, with a focus on high-profile statistical categories such as batting average, home runs, RBI, ERA, saves and strikeouts.

We then ranked them from least to most surprising, based on track record and expectations leading up to their season of league-leading output.

First, a few honorable mentions.

Honorable Mentions

Here are a few other surprising league leaders who didn't make the cut but are still deserving of a mention:

• Pedro Alvarez, PIT: 2013 NL home run leader (36)

• Michael Cuddyer, COL: 2013 NL batting average leader (.331)

• Josh Johnson, FLA: 2010 NL ERA leader (2.30)

• Derrek Lee, CHC: 2005 NL batting average leader (.335)

• Jason Motte, STL: 2012 NL save leader (42)

• Anibal Sanchez, DET: 2013 AL ERA leader (2.57)

• Jorge Soler, KC: 2019 AL home run leader (48)

• Bob Wickman, CLE: 2005 AL save leader in (45)

10. Chris Carter: 2016 NL Home Run Leader

2016 NL HR Leaderboard

Chris Carter: 41 HR
Nolan Arenado: 41 HR
Kris Bryant: 39 HR
Matt Kemp: 35 HR
Freddie Freeman: 34 HR

Look Back

Chris Carter slugged 90 home runs in three seasons with the Houston Astros, including a 37-homer season in 2014 that was good for second on the AL leaderboard behind Nelson Cruz's 40.

However, he also hit just .217/.312/.459 with a 33.7 percent strikeout rate during that time, which led to his non-tender following the 2015 season and left him as something of a forgotten man.

The Milwaukee Brewers scooped him up on a one-year, $2.5 million deal, and he tied for the NL lead with 41 long balls.

Despite that gaudy home run total, his .222 average and 206 strikeouts led to another non-tender that offseason. That speaks more to a broken arbitration system that over-emphasizes power numbers than anything else, but it was surprising to see the NL home run leader cut loose nonetheless.

9. Hideo Nomo: 2001 AL Strikeout Leader

2001 AL Strikeout Leaderboard

Hideo Nomo: 220 K
Mike Mussina: 214 K
Roger Clemens: 213 K
Barry Zito: 205 K
Bartolo Colon: 201 K

Look Back

Hideo Nomo was a bona fide phenom in 1995 when he made the transition from Japan to Major League Baseball, going 13-6 with a 2.54 ERA and an NL-leading 236 strikeouts in 191.1 innings to finish fourth in NL Cy Young voting.

After three strong seasons with the Los Angeles Dodgers, he saw his production dip in 1998, and he was traded to the New York Mets midseason.

He went on to post a middling 4.73 ERA (95 ERA+) while pitching for the Dodgers, Mets, Brewers and Tigers from 1998 through 2000, and interest was limited when he hit the free-agent market before the 2001 season.

The Boston Red Sox inked him to a one-year, $4.5 million deal to fill out the rotation behind Pedro Martinez, and Nomo's swing-and-miss stuff returned.

He led the AL in K's (220) and strikeouts per nine innings (10.0 K/9), though he also topped the league in walks (96). He then returned to the Dodgers for two more stellar seasons before fading, finishing his career with 1,918 strikeouts and 8.7 K/9.

8. Vinny Castilla: 2004 NL RBI Leader

2004 NL RBI Leaderboard

Vinny Castilla: 131 RBI
Scott Rolen: 124 RBI
Albert Pujols: 123 RBI
Adrian Beltre: 121 RBI
Miguel Cabrera: 112 RBI

Look Back

Vinny Castilla was a lethal slugger for the Colorado Rockies during the late 1990s, averaging 38 home runs and 112 RBI during the five-year span from 1995 through 1999.

In the subsequent four seasons, he spent time with the Tampa Bay Rays, Houston Astros and Atlanta Braves, and hit a middling .250/.289/.405 (77 OPS+) while averaging 16 home runs and 68 RBI.

When he returned to the Rockies on a one-year, $2.1 million deal for his age-36 season in 2004, it looked like his swan song. Instead, he posted a 109 OPS+ with 43 doubles, 35 home runs and a league-leading 131 RBI on a team that went 68-94.

As you might expect, a staggering amount of that damage was done at Coors Field:

• Home: .321/.379/.575, 14 HR, 80 RBI
• Away: .218/.281/.493, 21 HR, 51 RBI

Regardless, driving in 131 runs on a 94-loss team is no easy feat.

7. Justin Morneau: 2014 NL Batting Average Leader

2014 NL BA Leaderboard

Justin Morneau: .319 BA
Josh Harrison: .315 BA
Andrew McCutchen: .314 BA
Buster Posey: .311 BA
Ben Revere: .306 BA

Look Back

Justin Morneau was once one of the most feared sluggers in baseball, winning 2006 AL MVP honors and averaging 30 home runs and 118 RBI from 2006 through 2009 with the Minnesota Twins.

However, concussion issues derailed his career from there, and his best days seemed to be behind him when he joined the Colorado Rockies on a two-year, $12.5 million deal before the 2014 season.

Instead, he claimed the NL batting title in his Rockies debut.

While some may be quick to credit the move to Coors Field for his productivity, his home/road splits were not all that dramatic:

• Home: 289 PA, .327/.363/.515, 11 HR, 52 RBI
• Road: 261 PA, .309/.364/.475, 6 HR, 30 RBI

That said, his .319 average was the lowest mark to win a batting title since Terry Pendleton also hit .319 during the 1991 season with the Atlanta Braves.

6. Kevin Millwood: 2005 AL ERA Leader

2005 AL ER Leaderboard

Kevin Millwood: 2.86 ERA
Johan Santana: 2.87 ERA
Mark Buehrle: 3.12 ERA
Jarrod Washburn: 3.20 ERA
Carlos Silva: 3.44 ERA

Look Back

Kevin Millwood was an established MLB starter with a solid track record during his six seasons with the Atlanta Braves when he was traded to the Philadelphia Phillies for catcher Johnny Estrada in December 2002.

After a solid first season with the Phillies, he dealt with a strained elbow ligament in 2004 that limited him to 25 starts and a 4.85 ERA in 141 innings in a contract year.

The 30-year-old was forced to settle for a one-year, $7 million deal from the Cleveland Indians as a result, and he won the AL ERA title.

Millwood allowed five hits and one earned run over seven innings against the eventual World Series champion Chicago White Sox in his final start of the season to put the finishing touches on a surprising bounce-back campaign.

That earned him a five-year, $60 million contract from the Texas Rangers in free agency.

5. Chase Headley: 2012 NL RBI Leader

2012 NL RBI Leaderboard

Chase Headley: 115 RBI
Ryan Braun: 112 RBI
Alfonso Soriano: 108 RBI
Aramis Ramirez: 105 RBI
Hunter Pence: 104 RBI

Look Back

At the 2012 All-Star break, Chase Headley was tied for 36th in the NL with 42 RBI.

The 28-year-old had a career high of 64 RBI at the time, so he was well on his way to his best offensive season, but few could have guessed what was coming in the second half.

The San Diego Padres third baseman hit .308/.386/.592 with 23 home runs and 73 RBI in 75 games after the break, en route to an unlikely NL RBI title.

He never again topped 15 home runs or 70 RBI in a single season, making his 2012 second-half performance one of the most unlikely of the past 20 years.

4. R.A. Dickey: 2012 NL Strikeout Leader

2012 AL Strikeout Leaderboard

R.A. Dickey: 230 K
Clayton Kershaw: 229 K
Cole Hamels: 216 K
Cliff Lee: 207 K
Gio Gonzalez: 207 K

Look Back

R.A. Dickey had a 5.43 ERA in 442.2 career innings when he joined the New York Mets before the 2010 season.

The 35-year-old had reinvented himself as a knuckleballer in 2006 and found previously unknown success in 2010, going 11-9 with a 2.84 ERA, 1.19 WHIP in 174.1 innings.

While that breakout performance and similar success the following year made his run to NL Cy Young honors in 2012 less than shocking, the significant spike in his strikeout rate was unexpected.

In his first two seasons with the Mets, he struck out 238 batters in 383 innings for a 5.6 K/9 rate, but he led the NL with 230 strikeouts in 2012.

That gaudy total was due in part to the fact that he also led the NL with 233.2 innings, as his 8.9 K/9 checked in just eighth among qualified starters, but it was an unexpected jump in punchouts nonetheless.

The Mets wisely sold high on the heels of that performance, trading him to the Toronto Blue Jays for a package of players that included a young Noah Syndergaard.

3. Freddy Sanchez: 2006 NL Batting Average Leader

2006 NL BA Leaderboard

Freddy Sanchez: .344 BA
Miguel Cabrera: .339 BA
Albert Pujols: .331 BA
Garrett Atkins: .329 BA
Matt Holliday: .326 BA

Look Back

The Pittsburgh Pirates acquired Freddy Sanchez in the five-player deal at the 2003 trade deadline that sent veteran pitchers Jeff Suppan and Brandon Lyon to the Boston Red Sox.

Two years later, he saw his first extended MLB action in a super-utility role and hit .291/.336/.400 (93 OPS+) with 35 extra-base hits in 492 plate appearances.

Entering his age-28 season, he looked like a solid part-time player with limited upside.

Instead, he hit .344 to win the NL batting title while also leading the league in doubles (53) and ranking third in hits (200).

While that proved to be his peak, he was more than just a flash in the pan. He hit .304 the following season and made three All-Star appearances. He also won a World Series as a key contributor for the 2010 San Francisco Giants.

2. Bill Mueller: 2003 AL Batting Average Leader

2003 AL BA Leaderboard

Bill Mueller: .326 BA
Manny Ramirez: .325 BA
Derek Jeter: .324 BA
Vernon Wells: .317 BA
Magglio Ordonez: .317 BA

Look Back

Bill Mueller was a career .286 hitter when he joined the Boston Red Sox on a three-year, $6.7 million deal before the 2003 season.

However, he had never hit higher than .295 over a full year.

That made his .326 average more than a little shocking, and his 2003 season as a whole exceeded even the wildest of expectations.

He posted a 140 OPS+ with 45 doubles, 19 home runs and 85 RBI in a 5.6-WAR campaign, finishing 12th in AL MVP voting while taking home Silver Slugger honors.

Teammate Manny Ramirez hit a blistering .375 over the final month of the season to make things interesting in the AL batting-title race, but Mueller held on to edge him out by the narrowest of margins.

1. Bret Boone: 2001 AL RBI Leader

2001 AL RBI Leaderboard

Bret Boone: 141 RBI
Juan Gonzalez: 140 RBI
Alex Rodriguez: 135 RBI
Manny Ramirez: 125 RBI
Jim Thome: 124 RBI

Look Back

A strong defender with modest averages of 21 home runs and 77 RBI in the three years prior, Bret Boone nonetheless had to settle for a one-year, $3.25 million deal from the Seattle Mariners when he hit free agency following the 2000 season.

No one would have called Boone a power hitter, as he had career highs of 24 home runs and 95 RBI over his first nine seasons.

However, he was just that for a Mariners team that won 116 games.

The 32-year-old batted .331/.372/.578 (153 OPS+) with 37 doubles, 37 home runs and 141 RBI, narrowly edging Juan Gonzalez during his lone season with the Cleveland Indians for the AL RBI lead.

The 8.8 WAR that Boone posted during the 2001 season accounted for more than one-third of his career total of 22.9.

All stats courtesy of Baseball Reference and FanGraphs, unless otherwise noted.