White Sox waiting for Craig Kimbrel to return to form

Of all the things the White Sox want to tighten up, clean up or straighten out after they clinch the American League Central — besides the celebration mess they’ll undoubtedly leave in the visitors’ clubhouse at Progressive Field in Cleveland — none looms larger than having the bullpen in tip-top shape for the postseason.

Games in October are won and lost in the late innings. The Sox’ front office, knowing this to be true, acquired All-Star closer Craig Kimbrel from the Cubs at the trade deadline to pair him with their own All-Star closer, Liam Hendriks, and form what looked like an unbeatable back-end tandem.

Kimbrel didn’t come cheaply. The Sox gave up second baseman Nick Madrigal and reliever Codi Heuer to get him, but it looked like a master stroke of aggressiveness from a front office adding a big weapon to their World Series arsenal.

But eight weeks later, Kimbrel is struggling to command his four-seam fastball and sharp curveball, seemingly missing on his glove side more than times than not, and often by plenty.

There are 11 games left and 14 days before Game 1 of the ALDS, likely against the Astros on Oct. 7 in Houston. That should be enough time for Kimbrel and pitching coach Ethan Katz and assistant pitching coach Curt Hasler to figure it out.

They believe they are onto something.

“We’ve centered on a couple of simple things in his delivery that he continues to monitor,” said Hasler, who oversees the bullpen.

“There were some delivery things, how he wasn’t using his back leg. We looked at before-and-after video, and he saw right away and said, ‘That’s it.’ It’s not difficult.”

Pitchers have peaks and valleys, even Hall of Fame-caliber guys like Kimbrel, who pitched to a 0.49 ERA with the Cubs this season. Since coming to the Sox, Kimbrel — primarily working the eighth inning in what is now becoming a more familiar role — has posted a 5.78 ERA, giving up more hits (17) and home runs (four) in 19 innings than he did in 36‰ innings on the North Side (13 hits, one homer).

“Sometimes you see guys kind of start the season off on fire, trend up and then kind of hit a plateau,” catcher Yasmani Grandal said, “and they start coming down and then all of sudden they’re like, oh, they figured it out, and they start trending up again.”

But the front office must be thinking, ‘‘any time now, Craig.’’

And those who would be getting the ball to Kimbrel are almost as vital to the Sox’ World Series hopes. Michael Kopech’s ERA has climbed from 1.52 on July 30 to 3.69 with a September ERA of 5.40, albeit with 16 strikeouts and two walks over 8 innings. He is trending better with one earned run allowed in his last five outings, however. And Ryan Tepera, another deadline acquisition from the Cubs, cut his finger at his apartment and hasn’t pitched since Sept. 10. He hopes to pitch in three games before the postseason.

Left-hander Aaron Bummer (3.86 ERA) has struck out 10, walked one and allowed one run over nine appearances in September, and lefty Garrett Crochet hasn’t allowed a run in seven appearances this month, allowing three hits and one walk. Right-hander Jose Ruiz (2.89 ERA) is riding a streak of 10 consecutive scoreless outings dating to Aug. 25, mostly in lower-leverage situations.

And then there’s Hendriks (2.77 ERA, 34 saves), the least of the Sox’ worries. The AL saves leader has a remarkable strikeouts-to-walks ratio of 103 to seven, and looks to be rounding into playoff form with one run allowed in his last 14 appearances.

As everyone waits for Kimbrel, Hasler doesn’t seem worried.

“Number one, it’s not for lack of stuff,” Hasler said. “The stuff is coming out of his hand extremely well. The velocity is good, the sharpness, depth and late break of the breaking ball are good. He’s getting strikeouts.

“I have no doubt Craig will get it figured out and as the games get bigger he’ll step up even more. He’s a huge part of what we’re going to do. We’re going to hand the ball to Craig and Liam and absolutely be in real good shape.”

NOTE: The Sox and Tigers were rained out Wednesday, as were the Indians and Royals, leaving the Sox’ magic number to clinch the AL Central at 2. The Sox could clinch as soon as Thursday with one win in their doubleheader against the Indians.