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An overhauled approach has Bruce Zimmermann pitching his way into the Orioles future

Fewer fastballs, way more changeups, and added consistency have the hometown kid leading a much improved Orioles rotation

Kansas City Royals v Baltimore Orioles - Game Two Photo by Mitchell Layton/Getty Images

Watching the Orioles pitchers work this season has elicited a strange sensation for the fanbase. Largely gone is the frustration and anger at what had become the unit’s daily inability to get major league hitters out since 2018. What appears to have taken its place is a combination of vague satisfaction and an anticipatory anxiety about when it all comes crashing down.

Keep in mind, the Orioles still do not have a “good” rotation. They rank 18th in ERA, 18th in innings pitched, and 28th in strikeouts per nine innings. That all adds up to a below-average group. But it is at least competitive, and it keeps most games watchable. That is an important distinction from past seasons.

For now, the group has remained steady, weathering the season-ending injuries to John Means and Chris Ellis, promoting Kyle Bradish, and watching Tyler Wells slowly get the hang of this starter thing. This has been made possible by two rocks in the rotation: Jordan Lyles and Bruce Zimmermann.

Lyles has been slightly better than advertised. The veteran righty has given the team length and avoided home runs just enough to provide some value to the squad. But this blog isn’t about him.

Zimmermann has been the staff’s best pitcher this season. The southpaw has made six starts, and nearly each trip out to the mound has been a delight, including his latest effort to beat the Royals 4-2 on Sunday.

He leads active Orioles starters in just about every category: ERA (2.67), FIP (2.51), strikeouts (8.90 K/9), home run rate (0.30 HR/9), and more. In light of the Means injury, the Orioles needed a “stopper,” and Zimmermann has taken up that role.

All six of Zimmermann’s starts have taken place immediately following an Orioles loss. On four of those occasions, the O’s have then won Zimmermann’s start. It can seem like a small thing, but lengthy losing streaks often have a debilitating impact on locker rooms. Having a pitcher that has the ability to stop those skids from happening in the first place is a valuable tool.

The season is still young, and it wouldn’t be fair to draw any concrete conclusions based on 30 innings of a pitcher. but the data suggests that Zimmermann has overhauled his approach quite dramatically compared to 2021.

The Baltimore native’s fastball has lost over 1 mph (from 91.4 to 90.3) this past year. Hitters are having no problem against the offering (.480 batting average), and that can often be a harbinger of impending disaster for a pitcher’s career. The solution there has been to throw it far less and lean into Zimmermann’s terrific changeup.

Zimmermann’s fastball usage has dipped from 51.4% in his 2020 cameo, to 42.2% in 2021, and now 32.6% so far in 2022. The changeup, on the other hand, has jumped from 24.3% to 25.8% to 31.8%, respectively. And the pitch has gotten better, adding nearly two inches of horizontal break. That movement, paired with Zimmerman’s ability to bury the pitch at the bottom of the strike zone, has opposing hitters whiffing on the changeup 31.1% of the time, the highest rate of Zimmermann’s admittedly brief big league career.

The other pitch in Zimmermann’s arsenal that has taken a step forward is his slider. The velocity on the pitch is down from 86.1 to 84.8, but whiffs are up from 36.8% to a whopping 57.6%. Why? My best guess: Zimmermann’s changeup and slider look really similar out of the hand.

Both their velocity and release point have gotten closer to one another over the last year. The changeup averages 84 mph while the slider averages 84.8. Last year there was nearly a 2 mph difference between the two. And while Zimmermann has always had a rather clean, repeatable delivery with consistent release points, that has improved further this year. His vertical release for the changeup and slider are now only one-third of an inch apart whereas they were about two inches apart in 2021.

A chart showing how the vertical release point for Bruce Zimmermann’s pitches has gotten more consistent. (h/t Baseball Savant, Bruce Zimmermann)

Location, of course, is a key element in the slider’s success as well. Zimmermann is routinely able to place the slider down and in on righties or down and away against lefties.

But is this the real Zimmermann? Can he maintain this level of performance? Well, probably not, but he can still be pretty good.

So far, Zimmermann has only allowed one home run (Anthony Rendon), which translates to 3.6% of his fly balls turning into home runs. That’s probably not sustainable, especially since he is allowing just as many fly balls as previous seasons.

Righties are having similar success against Zimmermann this season as they have in years past, just without the power (yet.) His career batting average against righties is .275. So far this year it’s .272. Meanwhile, he has been dominating lefties to the tune of a .150/.191/.250 slash line. That is a marked improvement from his career (.272/.344/.432). It isn’t far-fetched to think a lefty that has seemingly improved his off-speed and breaking pitches can continue to succeed against same-sided hitters, but the degree to which he has done so is a bit extreme.

At the same time, some other peripherals suggest Zimmermann will be just fine. His BABIP is a bit elevated at .321, and his 4.12 xERA and 3.30 xFIP are both solid, especially for a backend rotation piece.

The Orioles don’t need Zimmermann to be an “ace.” They will depending on Grayson Rodriguez, D.L. Hall, or some future acquisition to eventually fill that role on a competitive team. But they did need at least one of their internal candidates to prove they could handle a rotation role of some significance moving forward. There is plenty of season to go, but Zimmermann is playing himself into the future plans of his hometown team.