Which budding MLB stars will break out in 2019? That's an interesting question.
Who will break out in 2020? That requires a particularly well-calibrated crystal ball.
Obviously it's impossible to predict with anything approaching 100 percent accuracy. But here are our picks for each team's 2020 breakout star, based on pedigree and a healthy dollop of gut feeling.
To be clear: Some of these players will debut this season (yay!), but all may be held back from full-blown stardom for at least a year due to age and service-time considerations.
American League East
Baltimore Orioles: OF Yusniel Diaz
Yusniel Diaz was the centerpiece of the trade that sent Manny Machado from the Baltimore Orioles to the Los Angeles Dodgers at the 2018 non-waiver trade deadline. Expectations are calibrated accordingly.
The 22-year-old has some developing to do. But he possesses five-tool potential and posted an .841 OPS in 2018 while rising as high as Double-A. He should get a look from the rebuilding O's by September and could be a permanent fixture next season.
Boston Red Sox: INF Michael Chavis
An 80-game performance-enhancing drug suspension sent Michael Chavis' stock southward in 2018. On the other hand, he posted a .919 OPS in 46 minor league contests and ascended to Triple-A.
He should get a long look this spring and may log some innings at second base, where beloved Sox veteran Dustin Pedroia is attempting an injury comeback but may soon be finished.
New York Yankees: OF Estevan Florial
We might be rushing Estevan Florial a tad. He's yet to play above High-A and turned 21 on Nov. 25.
That said, there could be vacancies in the New York Yankees' outfield depth chart as veterans such as Brett Gardner and Jacoby Ellsbury step aside. The likely trajectory is for Florial to debut in 2020 and assume a significant role in 2021, but he could push that timetable with his tantalizing mix of speed, power and arm strength.
Tampa Bay Rays: LHP/DH Brendan McKay
Two different oblique injuries limited Brendan McKay in 2018, but the 23-year-old is a legitimate two-way star in the Shohei Ohtani mold.
His fastball sits in the mid-90s and is augmented by a plus cutter and emerging curveball that give him the repertoire of a legitimate big league starting pitcher. Add the .727 OPS he posted while rising to High-A, and you've got the makings of a special player.
The Rays will understandably exercise caution, but the small-market franchise literally can't afford to hold McKay back unnecessarily.
Toronto Blue Jays: Vladimir Guerrero Jr.
Vladimir Guerrero Jr. tore through the minor leagues last season, rocketing from the rookie leagues to Triple-A and posting a .381 average and 1.073 OPS. The son of Vlad is ready for liftoff.
He also won't turn 20 until March 16 and will almost surely be held back by the Toronto Blue Jays because of service-time machinations.
Expect a late-season debut in 2019 and a full-blown breakout in 2020. In the meantime, ready your popcorn.
American League Central
Chicago White Sox: OF Eloy Jimenez
Eloy Jimenez hit .337 with a .961 OPS last season and played 55 of his 108 minor league games at Triple-A. He's got little to nothing left to prove at the MiLB level.
The Chicago White Sox might play service-time games, however, meaning Jimenez will get a look in 2019 but won't be allowed to fully shine until 2020.
Cleveland Indians: RHP Triston McKenzie
Triston McKenzie impressed as a 21-year-old at Double-A last season, posting a 2.68 ERA in 90.2 innings and holding opposing hitters to a .191 average.
His lanky 6'5", 165-pound frame raises durability concerns, but he has all the makings of a front-line starter and should be on the fast track in the Tribe's system.
Detroit Tigers: RHP Alex Faedo
The Detroit Tigers have several intriguing pitching prospects at the top of their farm system, including 21-year-old right-hander Casey Mize.
The closest arm to The Show, however, is 23-year-old Alex Faedo. A solid mid-90s fastball, plus slider and emerging changeup give him the repertoire of a No. 2 starter, and the rebuilding Tigers won't be afraid to speed him along.
Kansas City Royals: RHP Brady Singer
Right-hander Brady Singer went No. 18 overall in the 2018 amateur draft, and the Kansas City Royals may have gotten themselves a steal.
The 22-year-old has a polished three-pitch arsenal and the look and feel of a quality MLB starter. Expect him to rise quickly through K.C.'s system as the Royals embrace an overdue rebuild.
Minnesota Twins: OF Alex Kirilloff
Shortstop Royce Lewis has the highest ceiling in the Minnesota Twins farm system, but the 19-year-old is realistically at least two years from making a significant MLB impact.
In the meantime, the Twinkies can look forward to the arrival of 21-year-old outfielder Alex Kirilloff, who posted a .348 average and .970 OPS between Single-A and High-A and should be ready for his closeup by 2020.
American League West
Houston Astros: OF Kyle Tucker
The Houston Astros will give veteran right fielder Josh Reddick the benefit of the doubt in 2019, despite the .242/.318/.400 slash line he posted in 2018. By 2020, however, the position should belong to top outfield prospect Kyle Tucker.
Tucker hit .332 with a .989 OPS at Triple-A last season and made his big league debut. It's possible he'll force the issue this spring, but his breakout might be delayed one more year.
Los Angeles Angels: OF Jo Adell
The Mike Trout era may end in Anaheim after the 2020 season, when the best player on the planet is set to hit free agency. In the meantime, the Jo Adell era could begin.
He won't turn 20 years old until April 8, but the Los Angeles Angels prospect has serious helium after posting an .897 OPS and rising to Double-A.
Eye-opening power, plus speed and a strong arm will make it hard for the Halos to keep this kid down.
Oakland Athletics: LHP Jesus Luzardo
Jesus Luzardo struck out 129 hitters in 109.1 frames between High-A and Triple-A while posting a 2.88 ERA last season. The Oakland Athletics will exercise caution given past elbow issues, but the small-market underdogs can't wait forever.
Provided he remains healthy and continues to dominate, it's easy to imagine Luzardo occupying a prominent place in Oakland's rotation by 2020.
Seattle Mariners: LHP Justus Sheffield
Justus Sheffield made his MLB debut with the Yankees in 2018 before getting shipped to the Seattle Mariners in the James Paxton trade.
The rebuilding M's might thrust him into the spotlight in 2019, but he did deal with some command issues last season in the minors.
The touted southpaw profiles as a top-of-the-rotation talent, but it might take one more year before he realizes his potential.
Texas Rangers: OF Leody Taveras
Leody Taveras turned 20 years old on Sept. 8 and hasn't played an inning above High-A. His development could stall.
Then again, he flashed the speed to log 19 stolen bases and seven triples in 132 games while teasing the defensive tools to remain in center field.
The Texas Rangers are bound for a rebuild, and Taveras should soon take center stage.
National League East
Atlanta Braves: RHP Ian Anderson
Kyle Wright might be the next pitcher to break out in an Atlanta Braves system that isn't short on burgeoning arms.
But next up could be right-hander Ian Anderson, who struck out 142 hitters in 119.1 innings with a 2.49 ERA between High-A and Double-A.
His mid-90s fastball, plus curveball and promising work-in-progress changeup suggest he might be an elite starter in another year for the youthful Braves.
Miami Marlins: RHP Sixto Sanchez
Acquired from the Philadelphia Phillies in the J.T. Realmuto trade, right-hander Sixto Sanchez needs some polish before he plies his trade with the Miami Marlins.
Elbow and collarbone issues suffered last season raise concerns, but Sanchez has the triple-digit fastball velocity and promising off-speed offerings of a future ace.
The Miami Marlins don't need to rush him, but given their status as bare-bones rebuilders, the Fish have no reason to wait.
New York Mets: INF Andres Gimenez
Andres Gimenez hit .281 with a .347 on-base percentage between High-A and Double-A last season. He's only 20 years old, but he seems to be on the fast track for the New York Mets.
His MLB arrival will depend upon the performance of middle infielders such as former touted prospect Amed Rosario and veteran Robinson Cano. But there is a path to meaningful big league playing time for Gimenez by 2020.
Philadelphia Phillies: OF Adam Haseley
Infielder Alec Bohm and right-hander Adonis Medina are arguably better prospects, but outfielder Adam Haseley is probably the closest to a big league breakthrough with the Philadelphia Phillies.
The 22-year-old hit .305 while rising to Double-A and could be on the MLB doorstep. The Phils are in the mix for superstar free agents Bryce Harper and Manny Machado this winter, but that doesn't mean they won't find a spot for Haseley provided he keeps hitting.
Washington Nationals: INF Carter Kieboom
Outfielder Juan Soto already shed the prospect label with the Washington Nationals, and fellow outfielder Victor Robles should soon do the same.
That leaves infielder Carter Kieboom as the next in line to break through with the Nats.
Kieboom posted an .801 OPS last season while making the jump to Double-A. If he can add power this season, he could be set up for an impactful debut with the Nationals in 2020.
National League Central
Chicago Cubs: LHP Justin Steele
In a thin Chicago Cubs farm system, left-hander Justin Steele might be the closest to making an MLB impact.
A sinking fastball and improving curveball and changeup give him the tools to be a quality big league starter. If he harnesses his abilities in 2019, he could be on the fast track to Wrigley Field for a Cubs club that hasn't made much noise this winter and would surely love to develop from within.
Cincinnati Reds: 3B Nick Senzel
Nick Senzel posted an .887 OPS at Triple-A before a fractured right index finger ended his season. That aside, he's a polished hitter with all the tools to succeed at the highest level.
He's currently blocked on the Reds' infield depth chart by second baseman Scooter Gennett and third baseman Eugenio Suarez. But Senzel should knock on the door in 2019, however, and truly bust out in 2020.
Milwaukee Brewers: 2B Keston Hiura
A classic contact hitter, Keston Hiura has the bat control and ability to spray the ball to all fields, which should make him a prototypical No. 2 hitter.
The 22-year-old has yet to advance to Triple-A and thus is not quite ready for MLB action. If he repeats or improves upon the .821 OPS he posted between High-A and Double-A last season, however, he'll be plying his trade for the Milwaukee Brewers soon.
Pittsburgh Pirates: RHP Mitch Keller
Mitch Keller's curveball is a legitimate hammer-dropper. His fastball touches the high 90s. If he develops a quality third pitch, he could become an ace.
The 22-year-old advanced to Triple-A in 2018 and could debut with the Pittsburgh Pirates in 2019.
By 2020, he may be a key controllable piece of the cost-conscious Bucs' starting rotation.
St. Louis Cardinals: 3B Nolan Gorman
Assuming right-hander Alex Reyes puts his injury issues behind him and finally breaks through in 2019, the Cardinals' next big thing could be third baseman Nolan Gorman.
Gorman advanced to Single-A in 2018 and finished with a .949 OPS and 17 homers in 63 minor league games. He's only 18 years old, so 2020 is an optimistic appraisal of when he'll arrive at the highest level.
So far, however, he's given the Cards ample cause for optimism.
National League West
Arizona Diamondbacks: RHP Jon Duplantier
A sinking fastball, plus slider, strong curveball and emerging changeup helped Jon Duplantier post a 2.55 ERA between the rookie leagues and Double-A last season for the Arizona Diamondbacks.
He's missed time with elbow issues and arm fatigue, but he has the four-pitch repertoire of an ace and won't be held back by the retooling D-backs assuming he stays healthy.
Colorado Rockies: 3B Colton Welker
Top Colorado Rockies prospect Brendan Rodgers ought to get his big audition in 2019. In 2020, it could be Colton Welker's turn.
The Rockies may lose third baseman Nolan Arenado to free agency after next season. Welker hit .333 with an .872 OPS at High-A. The 21-year-old needs to prove himself at the higher levels, but those numbers look mighty promising for a guy who might soon take half of his hacks at Coors Field.
Los Angeles Dodgers: OF Alex Verdugo
The Los Angeles Dodgers shed some outfielders this winter when they sent Matt Kemp and Yasiel Puig to the Cincinnati Reds. Unless they wheel and deal some more, there might not be a place for top prospect Alex Verdugo in 2019.
At the moment, Verdugo is theoretically blocked on the depth chart by A.J. Pollock, Cody Bellinger, Chris Taylor, Enrique Hernandez and Andrew Toles. He could force the issue with a torrid spring, but more likely the Dodgers will stash him at Triple-A for a call-up at some point next season and a breakout in 2020...unless they use him as non-waiver deadline trade bait this summer.
San Diego Padres: INF Fernando Tatis Jr.
Fernando Tatis Jr. posted a .286/.355/.507 slash line with 16 home runs and 16 steals as a 19-year-old at Double-A last season.
The Friars won't promote him right away, but they can't keep him down for long.
With his height (6'3") and notable arm strength, Tatis could ultimately slide to third base. Then again, with his range and athletic ability, he could be an outsized shortstop in the Carlos Correa vein.
San Francisco Giants: C Joey Bart
Buster Posey will be the San Francisco Giants' catcher in 2019 the same way the sun will rise in the morning.
Yet, Posey turns 32 in March and is coming off hip surgery. Nothing lasts forever. Enter Joey Bart.
The Georgia Tech alum went No. 2 overall to the Giants in the 2018 draft and posted a .952 OPS in 51 minor league games. He's too young and raw to get more than a look in 2019, but the notion of Posey sliding to first base and ceding playing time behind the dish by 2020 is plausible bordering on likely.
All statistics courtesy of Baseball Reference.