2021 Pod Projections: Zach Plesac, A Review

Today, I share the final review of my pre-season Pod Projections posts. This time, we shift to a starting pitcher, Zach Plesac, whose original writeup is here. Plesac did post a sub-4.00 ERA during his 2019 debut, but it wasn’t backed by his skills, as he handily outperformed his ugly 5.13 SIERA. During the short 2020, he enjoyed a true breakout as his strikeout rate surged thanks to pitch mix changes. Let’s see how he did for an encore and how it compared to the projections.

Games Started & IP: 28 Projected | 25 Actual & 168 Projected | 142.2 Actual

Plesac ended up missing about a month and a half due to a fractured thumb, ensuring he missed both my games started and innings pitched projections. If he hadn’t gotten hurt, he would have likely beaten both. However, he did fall short of my projected 6 innings per start forecast, which isn’t surprising given that he posted an ugly 4.67 ERA, chasing him out of games earlier than many expected.

K%: 24.2% Projected | 16.7% Actual

Wowzers! Not only did he fail to hold his strikeout rate gains from 2020, but his mark actually fell below what he posted during his 2019 debut, which was already below average! I did not see that coming. In 2020, he threw his four-seamer less often, and increased the usage of his slider and changeup. That’s typically a positive change for strikeouts, and not only did the higher frequency of higher SwStk% pitches increase his strikeout rate, but the pitches themselves generated an even higher rate of whiffs than during 2019. In 2021, his individual pitch SwStk% reverted right back to their lower 2019 levels, but because he held onto some of his pitch mix changes, he was able to sustain a double digit SwStk% overall, though it was well down from 2020.

Unfortunately, his called strike rate was even lower than his down 2020, so combined with the drop in SwStk%, it resulted in a tiny strikeout rate, well below what anyone could have imagined. He has posted solid enough strikeout rates in the minors, so it’ll be interesting to see if he could bring his mark back above 20% again.

BB%: 6.7% Projected | 5.7% Actual

Unsurprisingly, Plesac couldn’t repeat that microscopic 2.9% walk rate he posted in 2020, but did manage to keep his mark well below the higher rate he posted during his 2019 debut. This looks like a more sustainable level.

GB%/LD%/FB%: 38.5% / 21.5% / 40.0% Projected | 45.3% / 16.6% / 38.2% Actual

I was close on the FB%, but Plesac traded in a bunch of line drives for grounders, which is a far more desirable outcome. Unfortunately, it’s mostly outside the pitcher’s control so there’s no reason to think he’ll come close to a 16.6% LD% again.

HR/FB%: 14.5% Projected | 13.3% Actual

The projection was actually below what I expected the AL starting pitcher league average HR/FB rate would be, but the new baseball brought that HR/FB rate back below 15%. Plesac ended up posting a mark that was just below the league average as I projected, but getting the league average wrong hurt here.

BABIP: .285 Projected | .263 Actual

I leaned on Statcast to determine whether Plesac was any bit deserving of such suppressed BABIP marks during his first two seasons in the Majors. The answer was a resounding no. Since the sample size was tiny, it seemed pretty clear that the likelihood this was just good fortune was high. It’s possible Plesac owned a skill not captured by the Statcast metrics, but we wouldn’t know that for several seasons to come. Therefore, I decided to heavily regress his BABIP projection toward the league average, but also acknowledge there’s a small possibility he does do something to keep those balls in play from falling for hits at the clip we would expect.

While his BABIP did rise, it still remained well below the league average. Part of that is definitely due to that low LD% and this season, Statcast agrees he deserved a better than average BABIP, but not this much better. At this point, he’s only about halfway to the number of balls in play required for BABIP to stabilize, so the best bet here continues to be that his BABIP is due for further regression toward league average, but perhaps not all the way there.

***

Below is Plesac’s final pitching line, along with my Pod Projected pitching line, and the other systems published at the time for comparison, with the best forecasts highlighted:

Naturally, Plesac fell short of innings and strikeouts, but even with the fewer innings, all the projection systems were in line with his win total. That’s just dumb luck! Had he not gotten hurt, my Win projection probably would have been closest simply because I was the highest at 11 and he only needed one more win to reach that total.

I’m not 100% positive how deep the projection systems go into a pitcher’s pitch mix and velocities. I know Steamer accounts for fastball velocity, but I’m not sure if any other systems do or if any of them account for pitch mix changes. I was the only projection under a 4.00 ERA and my K/9 was well above the rest. Why? Because I observed a pitch mix change that directly fueled his 2020 breakout. This time, my manual work failed me since Plesac was unable to repeat those results, but the process itself of being aware of the change should give me an advantage on average.

What’s really surprising is that I nailed the WHIP despite being far too bullish on his ERA. That was all because of BABIP, as I was the lowest forecast, though still not nearly bullish enough. Using Statcast and batted ball type distribution has allowed me to stray from automatically assuming a near league average BABIP for all starting pitchers.

He’ll be a real interesting guy next year. We know he has the control and he’s shown strikeout ability at times. I imagine his price will be relatively cheap this time around, so he might be well worth the gamble on the hopes he regains some (or all) of his 2020 magic.