The importance of ace starting pitchers was on full display during the 2019 World Series, which was replete with frontline starters in Gerrit Cole, Justin Verlander, Max Scherzer, Stephen Strasburg and Patrick Corbin.
Pitchers of this caliber are not easy to find, however, which is why Cole and Strasburg earned contracts totaling more than a $560 million in guaranteed money this past offseason. Given the going rate for top starters in free agency, a homegrown young ace is arguably the most valuable commodity a team can have.
With that in mind, here are 30 pitchers -- one for every team, as chosen by MLB.com's beat reporters -- with the potential to reach ace status.
American League East
Blue Jays: Nate Pearson
With all the raw physical tools that clubs covet in a homegrown ace and the mental game to put it all together, the sky is the limit for the flamethrowing Pearson (MLB's No. 8 overall prospect).
Orioles: Grayson Rodriguez
Pitching is the strength of the Orioles’ improving farm system, and the jewel is Rodriguez (MLB's No. 36 overall prospect), a 6-foot-5, 220-pound right-hander who features four average-or-better offerings he can throw consistently for strikes.
Rays: Tyler Glasnow
Due to a mild right forearm strain, Glasnow was limited to 12 starts in 2019, but that was all anyone needed to see in order to understand why he was once the No. 1 prospect in the Pirates’ organization. During the first six weeks of the season, Glasnow was arguably the best pitcher in the AL.
Red Sox: Noah Song
It’s unclear how much time Song will spend with the Red Sox over the next two years as he completes his Navy commitment, but it is clear that he has the best pure stuff of any prospect in Boston’s farm system.
Yankees: Clarke Schmidt
Schmidt opened eyes in Yankees camp this spring, flashing a polished three-pitch mix that vaulted him to the top of the list among the Bombers’ pitching prospects.
Read more on the AL East's future aces >
Indians: Aaron Civale
Civale's teammates and manager Terry Francona have mentioned seeing similarities between the right-hander and Corey Kluber, both in stuff and personality.
Royals: Jackson Kowar
The Royals’ pipeline of young pitching prospects could produce multiple aces, from Kowar to Brady Singer to Daniel Lynch to Kris Bubic and others. As one rival scout said during camp, “[Kowar] probably has the highest ceiling of that group.”
Tigers: Casey Mize
The Tigers' farm system has at least three potential frontline starters in its ranks, including former first-rounder Matt Manning and high-rising Tarik Skubal. Mize, the No. 1 overall Draft pick in 2018, could be the best of the bunch.
Twins: Jordan Balazovic
Balazovic has grown into his 6-foot-5 frame and cranked his fastball up to where he can sustain velocity in the mid-90s at times. After a strong 2019 season, the 21-year-old rocketed up prospect rankings to No. 86 on MLB Pipeline's overall list.
White Sox: Lucas Giolito
Giolito gets the nod among a group of truly viable candidates for the top of the White Sox rotation, if for no other reason than he showed flashes of being an ace in 2019, finishing tied for sixth in the AL Cy Young Award race.
Read more on the AL Central's future aces >
Angels: Griffin Canning
Canning reached the Majors quickly after being taken in the second round of the 2017 Draft out of UCLA and has the makeup and stuff to become the future ace of the staff, if he can stay healthy.
Astros: Lance McCullers Jr.
McCullers has yet to start more than 22 games in a season due to injuries, but the 26-year-old has flashed ace potential since he arrived in the big leagues in 2015.
Athletics: Jesus Luzardo
It's easy to see why the A's believe Luzardo can anchor their rotation for the next decade or so. The 22-year-old is rated as Oakland's No. 1 prospect and the second-best left-handed pitching prospect in baseball.
Mariners: Logan Gilbert
While the rebuilding Mariners have an interesting group of promising pitching prospects knocking on the door, the 22-year-old Gilbert is regarded as the one with the highest upside by most scouts.
Rangers: Hans Crouse
The Rangers are excited about the starting pitching they have stockpiled in their farm system, and Crouse is viewed as a potential top-of-the-rotation guy. A second-round Draft pick in 2017, Crouse throws 94-97 mph with a wipeout slider and a changeup with plus potential.
Read more on the AL West's future aces >
National League East
Braves: Ian Anderson
Anderson (MLB's No. 37 overall prospect) has a high ceiling that was on display when he recorded a 2.68 ERA with an 11.9 K/9 mark in Double-A last season. He could soon join 22-year-old Mike Soroka in Atlanta's rotation.
Marlins: Sixto Sanchez
Marlins fans already were having this debate in Spring Training -- Sanchez or Edward Cabrera? Sanchez gets the edge based on more consistent fastball command. But if all goes to plan, these two are expected to front the rotation for years to come.
Mets: Matthew Allan
If the Mets have their way, Jacob deGrom will remain their ace through the life of his contract, which runs through his age-36 season in 2024. At that point, Allan will be 23 years old, perhaps ready to make his own mark as the Mets’ next frontline starter.
Nationals: Andry Lara
The Nationals signed Lara for $1.25 million as their top pitching prospect in last year’s international class. The righty is only 17 years old, giving the baseball world a pretty big window to watch his development.
Phillies: Spencer Howard
The last time Phillies fans got this excited about a homegrown pitching prospect? Think back to Cole Hamels in 2006. Howard is worthy of the hype. MLB's No. 34 prospect has four out pitches, including a fastball that touched 99 mph in the Arizona Fall League.
Read more on the NL East's future aces >
Brewers: Corbin Burnes
Burnes had a rough year in 2019, but he's only 25, and his stuff is ace-caliber. Burnes' 95.2 mph average fastball puts him in the 80th percentile, and his spin numbers are elite. The tools are there for him to be a top starting pitcher.
Cardinals: Jack Flaherty
There's an argument to be made that Flaherty arrived as the Cardinals' ace during his historic second half last season, when he posted a 0.91 ERA after the All-Star break. Now the Cardinals are looking for him to stay on that path.
Cubs: Brailyn Marquez
Among the promising arms in the Cubs' pipeline, the most intriguing prospect with ace potential is by far Marquez (MLB's No. 68 overall prospect). The 6-foot-4 lefty has grown into one of the Minor Leagues' most powerful arms, hitting triple digits regularly and topping out at 102 mph in 2019.
Pirates: Mitch Keller
While he posted poor surface stats (1-5 record, 7.13 ERA) in the Majors last season, Keller struck out 28.6% of the batters he faced and walked only 7%. The 6-foot-2 right-hander, who turns 24 on Saturday, still has front-of-the-rotation potential.
Reds: Hunter Greene
During the 2018 SiriusXM All-Star Futures Game in Washington, all 19 pitches Greene threw registered at 100 mph or faster and his top velocity was 103.1 mph. The hope is that he'll be able to recapture that form once he returns from Tommy John surgery.
Read more on the NL Central's future aces >
D-backs: Zac Gallen
The D-backs acquired Gallen from the Marlins on July 31 last year in exchange for top prospect Jazz Chisholm. The 24-year-old ended up being the team’s best pitcher in the second half as he compiled a 2.89 ERA with a 10.9 K/9 mark over eight starts.
Dodgers: Walker Buehler
Buehler is the undisputed future ace of the Dodgers, if he isn’t already the current one. At just 25, he’s an All-Star with a 14-win season on the resume and has demonstrated he has the chops for October with a 0.853 postseason WHIP.
Giants: Tyler Beede
The Giants believe Beede has the potential to develop into a frontline starter, although he encountered a significant setback when he underwent Tommy John surgery last month.
Padres: MacKenzie Gore
Gore, who was the No. 3 overall selection in 2017, might soon sit at the front of one of the sport’s best young pitching staffs. The 21-year-old lefty, baseball’s top pitching prospect, has a polished four-pitch mix and excellent command of all of those pitches.
Rockies: Ryan Rolison
Rolison, a lefty taken in the first round of the 2018 Draft, impressed with his poise and easy delivery during his first Major League camp. The 22-year-old doesn't overpower but knows how to move his fastball and has desirable 12-to-6 movement on his curveball.
Read more on the NL West's future aces >