White Sox have pitching for depth in October

August 2nd, 2021

“We just want to win,” said two-time All-Star closer Liam Hendriks upon being asked how the White Sox bullpen would work with the addition of eight-time All-Star closer Craig Kimbrel, acquired from the Cubs on July 30, as the club attempted to defuse any notion of a closer controversy.

The White Sox have won, obviously. They were 60-43 entering Deadline Day, and they held playoff odds of 99.6% on July 30. (That's thanks in part to their own successful play, and in part to the dreary conditions of the other four AL Central clubs, who are a combined 191-229.) Kimbrel and fellow reliever Ryan Tepera, also picked up from the Cubs in a separate deal, won’t do much to help the Sox win the division title they were already guaranteed.

But bullpen deals like these aren't made for regular-season success. It’s to set the team up better for the postseason, to make sure Tony La Russa isn’t put in the situation that Rick Renteria was put in last October, when he was handed an undermanned pitching staff that didn’t have a third starter, then handled a playoff bullpen game poorly and was days later cut free for his efforts.

So: Are they set up well? Let’s talk about strikeouts.

As we noted when the Deadline passed, the 2021 White Sox already had the highest pitching strikeout rate in baseball, and then, by adding Kimbrel and Tepera to Hendriks, Aaron Bummer and Michael Kopech, gave themselves “five of the 50 relievers (minimum 25 innings pitched) with 30% or higher strikeout rates.” (That’s no longer strictly true after Tepera’s first two games with the White Sox, but you get the idea.)

So we got to thinking: Maybe season-long rankings aren’t the right way to look at this. After all, look at the eight pitchers in the Opening Day bullpen. Three of them were Evan Marshall, Codi Heuer and Matt Foster, who were fantastic last year (2.04 ERA), then abysmal this year (5.53), and are unlikely to be high-leverage parts of bullpens for the remainder of the season. (Marshall is injured; Heuer went to the Cubs in the Kimbrel deal; Foster is currently in Triple-A, where he’s admittedly been impressive.)

We say that because if you look at the season-long 2021 bullpen numbers, you’ll find that the White Sox are fourth in strikeout rate, as their 27.5% mark is just behind Milwaukee, Cleveland and the Cubs. Yet if you just look at the pitchers in the organization, they have the highest bullpen strikeout rate by a lot. A lot.

That ranking, for what it’s worth, includes all pitchers in the organization, so Foster and Marshall and so on (but not Heuer and other ex-Sox), which is nice because it includes pitchers who are still available options. Yet if you look just at the eight relievers on the roster today, now we’re talking about a 34% strikeout rate. That would be easily the highest reliever strikeout rate for a season in baseball history, though of course we’re being a little unfair there, comparing just the current Chicago eight to the full seasons of comings and goings for other clubs.

Still, even if you look at just this group in this season, then the going-forward projections at FanGraphs (which account not only for the projected production of each player, but how much playing time they're expected to have) shows that the White Sox have the No. 1 projected bullpen both overall and in strikeout rate. Though there's been some inconsistency lately (notably on Saturday, when Kopech was hit hard right after starter Dallas Keuchel was), it's hard to find any other bullpen better prepared to get some swings and misses than the current iteration of the 2021 White Sox. Not that the rotation is slouching: They have the second-highest starter strikeout rate, tops in the AL.

It’s not just a nice thing to have, anyway. Pitcher strikeout rate matters toward team victories considerably more than hitter strikeout rate does. Good news for Chicago, anyway, which has a league-average batting strikeout rate.

It's not quite as stark in the playoffs. Even so, we're reminded of something Eno Sarris first wrote in 2014 at FanGraphs and updated in 2019 at The Athletic ($), which is that, for batters, in October, more than in the regular season, "there’s a little evidence that making contact plays well in the postseason." Not super well, anyway, because the "small ball wins in October" myth is exactly that, and home runs -- hitting them, and preventing them -- are still king in the playoffs.

But in a much-smaller set of games in October, far more randomness can happen. So we went back to 2013 to try to answer this question: Will it matter more to miss bats than than it does in the regular season? The answer is: A little. Not a lot.

Win % for team that strikes out fewer times in a game, 2013-present

Regular season: .643
Postseason: .669

(This is looking at strikeout rate on each side, so it includes batting and pitching. So for example, in the clinching Game 6 of the World Series last year, the Rays struck out a whopping 47% of the time, while the victorious Dodgers were at 32%. Hitting is hard. Especially in October.)

It's the corollary to what Sarris discovered; if it helps a little more to make contact in the postseason than in the regular season, then it must help a little more to prevent that contact, too, and it does. Not a lot, but a little, and in the playoffs, sometimes getting that extra bit more is what makes the difference. Sometimes that one weak ball in play that goes your way really can mean everything. Preventing it can mean as much; the White Sox might be perfectly situated to do that.

There are a lot of good stories here in Chicago. There's Hendriks' transformation from mediocre swingman (4.72 ERA from 2011-18) to fire-breathing closer (2.00 ERA from 2019-21), and Bummer going from a pitch-to-contact sinkerballer to a genuine bat-misser who still gets grounders. There's Kopech going from being acquired as a huge prospect in the Chris Sale trade, injuring his elbow, then electing not to play in the 2020 season, and now becoming a reliable reliever after two years away.

There's Carlos Rodón's journey from third overall pick in the Draft to injury-plagued afterthought to legitimate Cy Young contender, and Lucas Giolito's own journey from being 2018's worst regular starter to collecting Cy Young votes the last two seasons, and Lance Lynn going from "innings eater" to "ace." There's Garrett Crochet going from the 2020 Draft to the playoffs within four months. More recently, there's Reynaldo López going from "forgotten member of the Giolito trade" to "deeply unimpressive starting pitcher" (4.76 ERA from 2017-20) to, quietly, "hard-throwing reliever who has an 11/1 K/BB in his last five outings."

Now, there's Kimbrel and Tepera, too. There's so much here. There's baseball's best strikeout staff, steaming toward the playoffs.