When you take a look around the landscape of Major League Baseball and talk about frontline, stud pitchers, a few terms are bounced around that sometimes might sound interchangeable. Most prominently, you might see “ace” or “No. 1 starter.”
For a long time, I was of the mind that a No. 1 starter meant one of the top 30 pitchers in baseball, given that there are 30 teams. If you lined every pitcher up and divided them evenly, that’s by literal definition a No. 1 starter. The word “ace” originates from a deck of cards and those are also “1.”
Sports terms evolve, though, and it seems like many people want to separate a No. 1 starter from a “true ace” these days.
What is a true ace? Well, some of it is feel. Let’s look back at last season and zero in on Tarik Skubal. The AL Cy Young winner, Skubal went 18-4 with a 2.39 ERA, 0.92 WHIP and 228 strikeouts against 35 walks in 192 innings. No one who knows anything about baseball would dispute that he’s a No. 1 starter. I think some might try to claim since he didn’t reach 200 innings or something that he isn’t a true ace, but c’mon. It was his first full season since 2021 and he had a major injury in there.
Look at Skubal in the playoffs and this is where the “feel” factor came in. The true mark of an ace as the term has come to be known is that you feel like it’s going to take absolutely everything to break right for the opponent to beat this pitcher.
Sure enough, the Tigers won his first two starts of the playoffs while he didn’t allow a single run in 13 innings. They were the inferior overall team, but the ace elevated them and they won. Things unraveled in Game 5 for him, but not until the fifth inning after four scoreless frames. He started his postseason career with 17 no-run innings.
That’s a true ace.
There shouldn’t be much disputing that, but if we’re going to draw a distinction, let’s look at the top 30 starting pitchers by FanGraphs’ WAR last season. Yes, I know we have to do this every time WAR is mentioned, but let’s be clear: I’m not saying WAR is the only stat that matters for pitchers or even the most important. It’s just the easiest way to sort by overall value.
If you look at Nos. 26-30 last year, you find Brandon Pfaadt, Hunter Brown, Shota Imanaga, Bailey Ober and Kevin Gausman. Gausman battled velocity issues early in the season and has been an ace in the past and while there’s plenty of potential in the rest of the group, I think we can all tell the difference between Tarik Skubal as an ace and Brandon Pfaadt not being an ace.
Over on Baseball Reference, Nos. 26-30 in starting pitcher WAR were Luis Gil, Tyler Anderson, Jack Flaherty, Brady Singer and Imanaga.
Again, cases can be made for a few of these names to be called frontline starters and sitting in the top 30 is, by definition, a “No. 1 starter,” but I think we can safely point to the distinction between anyone in this group and a true ace.
How many aces are there in baseball now? It’s slim pickings. It sure isn’t close to 30. Let’s try to find the True Aces for 2025.
True Aces
Tarik Skubal, Tigers
Not much more needs to be said. He’s my No. 1 ace entering 2025.
Zack Wheeler, Phillies
Two years ago, Gerrit Cole finally broke through and won a Cy Young after coming close many times. Last year, it was Chris Sale’s turn. Is Wheeler next? He hasn’t had as many close calls as the others, but he’s probably got the best remaining pedigree among pitchers who have never won the hardware before. He’s finished second twice, including last year, when he was 16-7 with a 2.57 ERA, 0.96 WHIP and 224 strikeouts in 200 innings.
Paul Skenes, Pirates
Perhaps a controversial choice, given that he only has 23 career starts, but it shouldn’t be. He’s firmly an ace already. He was 11-3 with a 1.96 ERA, 0.95 WHIP and 170 strikeouts in 133 innings.
Corbin Burnes, Diamondbacks
Burnes won the Cy Young in 2021 and has worked at least 190 innings in each of the following three regular seasons. He won 15 games with a 2.92 ERA for the Orioles last year and now goes to the NL West. I expect him to put up an ace-level year for the D-backs.
Chris Sale, Braves
Sale was absolutely an ace last year and has been for a lot of his career. The only worry now is his age. He turns 36 before the season starts and there’s a ton of mileage on that left arm with his spindly frame. He deserves to be up here, though, thanks to his 2024 performance.
Cole Ragans, Royals
In his first full season with the Royals, Ragans was a popular breakout pick but then late in the season it felt like, if anything, he was being overlooked. In 32 starts, he had a 3.14 ERA and 223 strikeouts across 186 ⅓ innings. He’s entering his age-27 year and coming off a fourth-place finish in AL Cy Young voting.
Logan Webb, Giants
The trusty Webb has led the NL in innings pitched each of the last two seasons. He’s finished second and then sixth in Cy Young voting. In his last four seasons, he’s posted a 3.18 ERA (126 ERA+) and 1.14 WHIP. He doesn’t feel like a 2025 ace at times because he often pitches to contact instead of striking everyone out, but he still fanned 172 last year.
Dylan Cease, Padres
The walks are always going to be a slight concern, but he’s pitched around them enough that I’m not as worried now. He’s now finished second in Cy Young voting in the AL (2022) and fourth in the NL (last season). He’s averaged 223 strikeouts a season over the course of the last four years, during which time he’s pitched to a 3.52 ERA (120 ERA+).
Framber Valdez, Astros
I wrestled with Valdez and Cease a lot on whether or not they belong up here in the top tier. Valdez in the last three years has gone 44-24 with a 3.06 ERA (131 ERA+), 1.13 WHIP and an average of 192 innings and 188 strikeouts per season. He’s been a frontline starter for a team that’s won the World Series and makes the playoffs every single year. He’s finished fifth, seventh and ninth in Cy Young voting. He’s an ace.
Possibly True Ace, Possibly Not
Spencer Strider, Braves
Strider is 100% a true ace as long as he’s uncompromised. We just don’t know when he’s returning from major surgery and how much the training wheels stay on early in the season.
Sandy Alcantara, Marlins
Similar sentiment for Alcantara. He’s a true ace when fully functional, but he missed all of last season after having Tommy John surgery. He’s ahead of Strider with his rehab having been completed, though, and he’s the Marlins’ Opening Day starter.
Hunter Greene, Reds
I toyed with putting Greene above as a true ace already. He broke through with an All-Star season in 2024, posting a sparkling 2.75 ERA (160 ERA+), but he achieved his career high with only 150 ⅓ innings. We’ve got to see more than that before declaring him on the top tier.
Gerrit Cole, Yankees
The 2023 Cy Young winner has been toward the top of the ace list many years, but he dealt with an injury in the first portion of last season and then battled inconsistency upon returning. He looked the part in Game 5 of the World Series before his entire team fell apart in the fifth inning and it wouldn’t be remotely surprising to see him return to the level of a true ace.
Shane McClanahan, Rays
In his three-year career, McClanahan is 33-16 with a 3.02 ERA and 1.11 WHIP. He was a full-on ace entering 2023, but had to undergo Tommy John surgery in late August. He’s back now, though.
Garrett Crochet, Red Sox
The 6-foot-6 lefty is a former first-round pick and looked the part a lot last season. He also only worked 146 innings and his previous career high was 54 ⅓. He only threw 38 ⅔ innings after the All-Star break last year and posted a 5.12 ERA. The talent is there and it’s why the Red Sox traded for him, but there are questions to be answered before we view him as an ace.
George Kirby, Mariners
Kirby is a good candidate to take the next leap forward into acedom. Maybe the move is not throwing so many strikes? He might be the best control artist in the majors, having only walked 64 batters in 511 ⅔ career innings. He also led the AL in hits allowed last season, though, likely due to too much predictability when it comes to pitching inside the strike zone.
Tyler Glasnow, Dodgers
Glasnow has 100% looked like an ace for long stretches and has Cy Young talent, but he’s never thrown more than the 134 innings he did last season and he was injured for the entirety of the playoffs. That’s what is holding him back.
Aaron Nola, Phillies
Opposite of Glasnow, Nola has been an innings eater through the course of his career. He’s topped 200 innings three times and 190 two other times. At this point, his run prevention isn’t reliable enough to call him an ace, though. He had a 4.46 ERA in 2023 and lowered it to 3.57 last year, though that’s still a 114 ERA+. It’s good but not great and with two of the last four years sitting below average, it’s enough to say he’s more workhorse than ace.
Seth Lugo, Royals
Lugo was a bona fide ace last season. He was the runner-up in Cy Young voting in the AL with a 3.00 ERA, 1.09 WHIP and 181 strikeouts in 206 ⅔ innings. He’s not listed as a true ace because he was 34 years old and had never been an ace before. It’s tough to repeat. It’s entirely possible that he does.
Reynaldo López, Braves
López was certainly an ace when on the mound last year, as illustrated by his 1.99 ERA. He only managed 135 ⅔ innings, though, and he’d never before been an ace. He’s now 31. It would be foolish to leave him off this list, but it might be just as folly to assume he’s on the top line.
Yoshinobu Yamamoto, Dodgers
We caught some glimpses of the ace-like prowess of Yamamoto last year, both in the regular season and World Series. We just only saw it in 90 innings of regular-season work. He’s a better bet than many on this portion of the list, but he still can’t be called a no-doubt, true ace right now.
Roki Sasaki, Dodgers
He has ace potential, that’s for sure. He’s also a newbie.
Blake Snell, Dodgers
Which Snell shows up? The 2018 Cy Young winner or the one who had a 4.06 ERA (101 ERA+) the following three seasons? The 2023 Cy Young winner or the one who started last season with a 5.40 ERA through nine starts? Or the dude who went 13-3 with a 1.20 ERA in his final 23 starts?
I think it’s more likely than not that Snell is an ace, but he’s proven it isn’t a sure thing for quite a while.
Logan Gilbert, Mariners
Gilbert led the majors in innings pitched and WHIP (0.89!) last season, striking out 220 with a 3.23 ERA in his 208 ⅔ innings. He’s close to ace level but we probably need to see more domination given his pitcher-friendly home ballpark. He only had a 113 ERA+, for example.
Max Fried, Yankees
The southpaw was definitely an ace from 2020-22 and injury held him to 14 ace-like starts in 2023. Is he compromised? He took a step back in 2024, though was still a frontline starter who worked 174 ⅓ innings. It wouldn’t be shocking in the least to see him throw like an ace this year.
Michael King, Padres
It needs to happen for a longer period of time but King was magnificent down the stretch. He went 9-5 with a 2.24 ERA in his last 20 regular-season games last year. He was dominant in his first playoff start before getting knocked around by the Dodgers in his next one.
Jacob deGrom, Rangers
It might feel like a long shot due to his injury history, but deGrom returned from Tommy John surgery to make three starts last year. He was held to 10 ⅔ innings but had a 1.69 ERA and struck out 14 against only one walk. If he can somehow muster something like 175 innings this season, the odds would be overwhelmingly in his favor of being a true ace.
Some others who could leap up into being a true ace: Cristopher Sánchez, Shota Imanaga, Justin Steele, Pablo López, Tanner Houck, Ranger Suárez, Grayson Rodríguez, Yusei Kikuchi, Hunter Brown
Some others who could return to form as true aces: Shane Bieber, Sonny Gray, Kevin Gausman, Luis Castillo, Zac Gallen, Shohei Ohtani and, though it would be surprising, Justin Verlander, Max Scherzer and Clayton Kershaw.
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