After getting shelled by the Blue Jays in the post-rain delay portion of his start on May 16, Zack Wheeler owned an ugly 5.92 ERA on the season. That start marked the second time in his past three at the time in which he got rocked, with the Rockies having gotten to him for eight runs in six innings on May 4.

Since that Blue Jays debacle, though, Wheeler has put together one of his better stretches of pitching at the major league level. Over four starts, he’s thrown 25.0 innings with a 2.52 ERA, 24 strikeouts, and he’s issued just five walks and allowed one home run. To be fair, two of those starts came against bad teams: the Marlins and the Orioles. But the other two came against the Brewers and Cubs, teams with a real shot at making the playoffs. But all of those numbers look far better than what he had done in the seven starts that led up to this stretch of success.

Before the four-start stretch of success, here’s how it broke down:

  • four-seam fastball, 62.44%
  • slider, 14.93%
  • changeup, 11.88%
  • curveball, 10.11%
  • splitter, 0.64%

As far as pitch usage goes, here’s the breakdown over the past four starts per Brooks Baseball:

  • four-seam fastball, 59.47%
  • slider, 18.69%
  • curveball, 9.22%
  • changeup, 8.74%
  • splitter, 3.88%

The fastball has still been Wheeler’s bread and butter, but he’s upped the use of his slider, slightly reduced his use of the change and curve, and introduced a brand new pitch in his splitter, which made its debut earlier this year. And while he hasn’t thrown it super often, the pitcher has a 15.0 percent whiff rate in total this year, the highest mark of any one of his pitches. The uptick in slider usage shouldn’t be ignored, either. That pitch made a great first impression this year, and it’s still sitting at a 12.35 whiff rate.

On top of those changes, Wheeler has just plain thrown harder in three of these four starts, averaging 97.36, 96.82, 97.81, and 95.43 miles per hour with his fastball in them, respectively. The first three of those were his highest of this season by quite a bit, and in all of them, he had the slider averaging roughly 92-and-a-half miles per hour, too.

Pitch usage and velocity might not explain everything, but maybe the current repertoire just works better, whether that means keeping hitters off balance, throwing more strikes, or just preventing opponents from barreling up the ball and hitting it over the fence. It’ll be interesting to see whether or not he hits those high marks in velocity more often moving forward and what he does with his mix of pitches, especially the splitter. There probably won’t be any major revelations here, but right now, it at least looks like it’s possible that the good version of pre-Tommy John Zack Wheeler might make a return. Compared to where things stood even just a few weeks ago, that’s a big improvement.