Shockingly, Jordan Zimmermann Appears to Be Back

Coming into the 2018 season, it looked like Jordan Zimmermann was finished as a fantasy-relevant starting pitcher. He was entering his age-32 season, and he had essentially been a train wreck ever since he turned 30. In other words, I certainly didn’t expect to be sitting here in July 2018 recommending Zimmermann in basically any fantasy format.

After a strong first month in a Tigers uniform in 2016, Zimmermann unraveled entirely. As for that month of April, it wasn’t without its warning signs either — even though he pitched to a pristine 0.55 ERA in his first 33 innings as a Tiger, he just wasn’t missing many bats, as his 6.27 K/9 indicated. He was getting outs, but for a guy who recorded strikeout rates of 8.20 K/9 and 7.32 K/9 in his previous two seasons with the Nationals, that was a pretty steep drop — even for a guy moving from the National League to the American League.

As soon as the 2016 calendar turned to May, Zimmermann experienced a meltdown that lasted for about two full years:

• May-Sept 2016:
  • 72.1 IP, 6.84 ERA, 1.51 WHIP, 5.4 K/9, 2.4 BB/9, 1.6 HR/9
• 2017 Season:
  • 160 IP, 6.08 ERA, 1.55 WHIP, 5.8 K/9, 2.5 BB/9, 1.6 HR/9

He continued to allow way too many runs in April 2018 (5.81 ERA), but there were also some signs that he might finally be turning it back around after two years plagued by nagging injuries to his neck and back. He struck out 27 batters in 26.1 IP in April — which was the first time he averaged more than a strikeout per inning in any month since August 2015 — but when he hit the disabled list with shoulder discomfort in early May, it looked like he might be heading for another lost season in Detroit.

However, after spending just under six weeks on the DL, Zimmermann returned and immediately continued the hot stretch he’d started before he went down. Check out what he’s now done in his last six starts (two before the injury, four since):

• 37 IP, 1.22 ERA, 0.70 WHIP, 8.3 K/9, 1.2 BB/9, 0.2 HR/9

On the one hand, it’s only a six-start sample. On the other hand, Zimmermann hadn’t strung together six strong starts in a row since his first six starts in a Tiger uniform to begin 2016. When I dove into the underlying stats supporting Zimmermann’s surprising resurgence, I found myself believing in him enough to pick him up in a 12-team mixed league. Let’s see if you agree that he’s worth a shot.

In his post-game interview after Friday’s brilliant performance (8 IP, 1 ER, 4 H, 0 BB, 11 K) against the Rangers — arguably his best start since 2014 — Zimmermann made a comment that I found quite interesting:

“The slider’s the best it’s ever been. The fastball has been down a few miles per hour, but I still have other weapons I can go to.”

It’s important to note that Zimmermann is still “only” 32 years old, and while he’s lost a little bit of velocity over the years — he averaged 93.9 mph at his peak in 2012-2013, and today sits at 91.2 mph — it’s not like he’s Felix Hernandez, another 32-year-old righty who has lost nearly 7 mph of velo since his peak. So, yes, the fastball is down a bit, but Zimmermann was never all that reliant on blowing hitters away to begin with.

The reason I found Zimmermann’s quote from Friday so intriguing is that the slider has always been his best pitch. Even when he was sitting comfortably at 94 mph and dialing up 96 mph at times, Zimm’s best weapon was his slider. So, for him to be saying today that he’s never thrown it this well before is a pretty significant statement.

Digging into his data a bit further, I found a relatively simple explanation for why he’s been so good this year: His slider is as effective as it’s ever been, and he’s throwing it far more frequently than ever before. Zimmermann’s throwing his slider 34.9% of the time this year, which is a major departure from last year when he threw just 24.3% sliders. It’s also way beyond his career average of 22.5% sliders. In fact, only six qualified pitchers in baseball this year are throwing sliders more frequently than Zimmermann is, and only one of them (Luis Severino, 2.74 wSL/C) is throwing them more effectively than Zimm (2.20 wSL/C).

Additionally, he’s seeing better results with his curve than ever before. He’s throwing that pitch 15.1% of the time, which is more or less on par with his curveball usage over the last few seasons, but this year his curve has an excellent rating of 3.97 wCU/C. When you compare the pitch to previous iterations of his curveball, it’s clear that Zimmermann is getting more movement with his curve this year.

You can see in these graphs that he’s getting more significant vertical drop on the curve this year, and also that both his slider and curve are getting a bit more horizontal movement than they did last year as well.

2017:

2018:

Based on comments from Zimmermann and manager Ron Gardenhire, it seems the consensus is that Zimm simply hasn’t been healthy enough in the last couple years to get the most of his stuff. It would make sense that his now-healthy neck and back are enabling him to throw all of his pitches with more conviction.

Regardless of the reasoning, the results are impossible to question. Zimmermann’s swinging strike rate is currently the second-highest of his career at 10.2%, which is a sharp increase from the 8.1% whiff rate he posted last year, or his 7.7% from 2016. Even more interesting is the fact that he’s throwing fewer pitches in the strike zone than ever before (43.3% Zone), but he’s still generating roughly the same amount of swings (48.1% in ’18, 49.1% in ’17, 48.4% in ’16). That combination is driving a career-low 78.7% contact rate, which just so happens to include a ton of soft contact (22.5% Soft).

I know Zimmermann had an ERA over 6.00 last year, and that he was striking out fewer than 6 K/9 for the last two years, which certainly doesn’t make his rejuvenation easy to buy into, no matter what the trends say now. Still, the guy is doing everything well right now, and he says he feels better physically than he has in years.

The injury risk is obviously there, as evidenced by the fact that he’s already been on the DL once this year, but the production looks legit to me. I honestly didn’t expect to find nearly as many positives in his data as I did. As long as he stays healthy, I’m confident that his success is relatively sustainable — confident enough that I’ve put my money where my mouth is and rostered him on my own fantasy teams. I suggest you do the same before someone else does.