Now that the division series are set, I wanted to do a MLB playoffs-flavored update to my in-season ace rankings. I'm including only players on teams still alive (sorry, Gerrit Cole), and only those currently healthy (sorry, Clayton Kershaw) and instead of projecting for the next season or two, this ranking is based on value for this postseason alone.
That means past postseason experience means more than in a conventional ace ranking (and in many cases will act as a tiebreaker), while 2021 performance and current form mean more than a multiseason track record, though I'd like to have both. So don't read this as "definite ace who had a down season is now behind an upstart with a bounce-back season for 2022"; read it as "Kiley would rather have this hot hand for the next few weeks." Some of these guys will also be used out of the bullpen, maybe exclusively, but that doesn't diminish for me what they could do as a starter, if given the shot.
Tier 1
1. Corbin Burnes, RHP, Milwaukee Brewers
You could put these four in any order, hence the tier system. Burnes pretty clearly had the best 2021, but also has the least playoff experience and fewest career starts, so you could reasonably lean toward a little more track record with the others. Burnes posted the highest pitching fWAR total we've seen in the past three seasons (7.5 WAR). Over the past 10 seasons, that's beaten only by 2018 Jacob deGrom (9.0), 2015 Kershaw (8.6), 2014 Kershaw (7.9) and 2017 Chris Sale (7.6).
2. Walker Buehler, RHP, Los Angeles Dodgers
Buehler's average fastball velocity is down 1.5 mph this year (96.9 to 95.4 mph, though ticking up late in the season) and his fastball usage is also down over 10%, but he's been humming along at that low-3s ERA talent level his entire MLB career, posting a career-high 207.2 innings this year. He's tied for second with Charlie Morton (behind only teammate Max Scherzer) for most postseason innings among those in the playoffs this year and, by any measure, has been one of the best playoff-performing pitchers of anyone in this year's crop.
3. Max Scherzer, RHP, Los Angeles Dodgers
Scherzer didn't have his best command in the NL Wild Card Game, but he had one of the best seasons of his career this year, at age 37, with comparable raw stuff to his best seasons, and he has the best all-around playoff track record of anyone in the playoffs this year. It also helps my comfort level that he has his trademark Mad Max intensity on the mound.
4. Brandon Woodruff, RHP, Milwaukee Brewers
The tops of the Dodgers' and Brewers' rotations should help anyone looking for a separator in their playoff picks decide to choose these two teams to meet in the National League Championship Series. Woodruff was decent as a rookie in 2017, mostly a reliever in 2018, then from 2019 to 2021 posted 374.2 IP of 3.00 ERA pitching over 65 starts. His somewhat limited playoff experience (21.0 innings over 6 appearances and 3 starts) has been very strong (2.57 ERA, even better peripherals), so don't be surprised if he ends up the best performer this fall of this clear top four.
Tier 2
5. Nathan Eovaldi, RHP, Boston Red Sox
Eovaldi kicks off a deep Tier 2 on the back of his two-year rebound from a World Series hangover. It helps him win some coin flips that he (1) sits 96-98 mph, (2) was good earlier this week in a do-or-die start against the Yankees, and (3) was also great in his other postseason experience in 2018 where (4) he won a ring. You could argue a number of orders for the pitchers ranked fifth through almost 20th, but I feel best about Eovaldi of that group right this second.
6. Julio Urias, LHP, Los Angeles Dodgers
Urias has flown a bit under the radar as an elite young starter due to the deep staff he's on. He just turned 25 and has thrown over 300 innings with an ERA under 3.50 in each of the past three seasons, with 33 playoff innings of similar quality over the same span. There might not be true ace upside, but he's not that far away, and he's steady.
7. Kevin Gausman, RHP, San Francisco Giants
Gausman is the shining example of what the Giants' Play-Doh Extruder of Pitching Excellence is capable of producing. The former No. 4 overall pick in 2012 had a solid midrotation-caliber career through 2019, averaging a 4.30 ERA with 8.3 K/9. For the past two seasons with San Francisco, Gausman has posted 251.2 innings of 3.00 ERA (not lucky, either: 3.02 FIP) and a 10.9 K/9, posting more WAR in that span than Yu Darvish and Buehler. This is why he's due to cash in this winter.
8. Charlie Morton, RHP, Atlanta Braves
Morton is tied with Buehler for the second-most playoff innings of this year's starters (61.1 innings), both well behind Scherzer's 116.1. He'll be 38 soon, but he's still sitting 94-97 mph with every indicator (and his actual ERA) saying he's a low-3s ERA type, as he has been over his long postseason career, due in large part to his low-80s Uncle Charlie.
9. Lance Lynn, RHP, Chicago White Sox
Lynn is in the Morton mold of a grizzled veteran with lively stuff and lots of playoff experience. They get there a little differently in terms of style but are of similar quality, with Morton getting the slight nod due to recent playoff performance.
t-10. Chris Sale, LHP, Boston Red Sox
t-10. Carlos Rodon, LHP, Chicago White Sox
I know it's a copout to do a tie, but I can't leave either of these pitchers out for totally different reasons. You can't do a playoff ace ranking and not have a healthy Chris Sale on the list, even if he's only nine starts back from surgery and appears to be one notch behind his hellacious peak. Rodon's 2021 comeback was miraculous given he was non-tendered last winter and re-signed for $3 million; he's also due for a payday this winter. Rodon had shown only glimpses of his potential as the 2014 No. 3 overall pick until 2021, then his season (132.2 IP, 12.6 K/9, 2.37 ERA that isn't that lucky per his peripherals) was in line with the pitchers in Tier 1 of this list. He's ranked down here as a hedge given the short track record, his lack of playoff experience and the fact that he almost didn't make the roster for this round due to arm soreness and falling velocity; he's as high variance as they come.
Others 11-20: Max Fried, Lucas Giolito, Lance McCullers Jr., Logan Webb, Framber Valdez, Dylan Cease, Shane McClanahan, Ian Anderson, Freddy Peralta, Alex Wood
Others 21-30: Anthony DeSclafani, Luis Garcia, Huascar Ynoa, Tanner Houck, Eduardo Rodriguez, Adrian Houser, Jose Urquidy, Tony Gonsolin, Eric Lauer, Nick Pivetta