Jacob deGrom and Max Scherzer at the top of the Mets’ rotation seems too good to be true, even if we consider the health concerns of the former and the…advanced baseball age of the latter. There are multiple question marks beyond their two aces, however, and perhaps none are quite as bewildering as Taijuan Walker.

The Mets signed Walker just after the official start of Spring Training last season, and despite some success in his return from Tommy John surgery he was somewhat of a consolation prize if obviously more than simply a depth signing. While we can’t know for sure why he didn’t have more suitors, it’s not unreasonable to attribute his lack of a market to a combination of his injury history and the discrepancy between his shiny 2.70 ERA in 2020 and its accompanying 4.57 FIP. Still, it seemed as worthy a gamble as any to help flesh out the team’s rotation heading into the season.

For roughly the first half of the 2021 campaign, Walker seemed like the steal of the offseason. He was mowing down opposing hitters on his way to his first All-Star nod while outpacing his career norms almost across the board. His 2.66 first-half ERA was accompanied by a more palatable 3.06 FIP, assuaging some of the concerns regarding another performance mirage. It appeared as though we were witnessing a remarkable career resurrection, and it was happening on the Mets no less.

Then some unseen switch flipped and his second half descent commenced with an absolute disaster of a July. He surrendered 20 runs in 20 innings while walking 13, giving up 24 hits, and getting clobbered for six home runs. It was a shellacking in every sense of the word. He recovered slightly in August, but overall his second-half numbers were ugly. His 7.13 ERA was accompanied by a 6.79 FIP, his K% plummeted, his BB% rose, and his HR/9 skyrocketed.

The elephant in the room, of course, is how the timeline of his downturn lines up suspiciously well with MLB’s renewed enforcement of their foreign substances ban. Those substances tend to help pitchers achieve higher spin rates on certain pitches, which in turn affects the movement of said pitches. The ban enforcement led to drops in spin rates league-wide, a reduction in strikeouts, and an uptick in walks. What does Statcast say about Walker’s spin rate across 2021?

Well, it doesn’t look good for our hero. The picture is even more damning when we group all of his pitches together to reduce the scale of the chart.

We obviously don’t know for sure whether Walker was using banned substances to bolster his stuff, but we can clearly see a significant drop coinciding with MLB’s actual enforcement of the ban. Many pitchers used substances to improve their grip on the slick ball without going to the extremes of something like Spider Tack, so it wouldn’t be surprising if he did use something. Was the theoretical removal of its use enough to throw his season off that much? It’s certainly possible.

It’s equally possible that fatigue played a major role in his mid-season reversal of fortune. His 94.2 innings in the first half were almost double his total of 53.1 during the COVID-shortened 2020 season and more than he pitched from 2018 through 2020 combined. He could have simply hit a wall and run out of gas fairly early into the 2021 season.

Another potential reason for the reduction in positive outcomes could be a change in his approach. Per the Baseball Savant screenshot below, his sinker was by far his best pitch in 2021.

The sinker is becoming less prevalent as pitchers opt for focusing more on the high-spin four-seam fastball up in the strike zone that has successfully (likely with assistance from the aforementioned substances) helped negate hitter adjustments to pitches in the lower half of the zone. Seemingly inexplicably, Walker dramatically reduced his sinker usage while at the same time increasing the use of his four-seamer right around the time his season turned upside down.

Why the change? It’s unclear, but it should be noted that increasing the usage of his four-seamer seems to be the exact opposite step to take to combat either fatigue or the inability to use foreign substances. It’s perplexing, really.

The explanation for his performance in the second half is likely some combination of all of the above, struggling to adjust to hitters adjusting to his early success, and/or other reasons that haven’t been made public (i.e. an injury).

It’s unclear what this all means for Walker and the Mets in 2022. Despite his mid-season collapse, Walker remains a pitcher with quality stuff that flashes dominant for stretches. His volatility means he can’t be depended on as more than a solid back-of-the-rotation starter with upside still in the tank, and that requires that the Mets make additional moves to add some certainty to the middle of their starting five (or six). The team will have had ample time to prepare for the frenzy that’s sure to ensue after the lockout ends, and it’ll be interesting to see which direction they go to address that uncertainty.

7 comments on “Taijuan Walker’s Jekyll and Hyde season

  • Metsense

    Very good research Rob. Your conclusions about the spin rate are evident and the fatigue could have been factor also. The change from sinker of the fourseam is the key. Heffner, Rojas, the analytics department and the catcher should shoulder part of the blame also, although Walker ultimately is responsible to throw the ball and take control of his own career.
    Strangely his 2021 FIP is in the neighborhood of his career FIP. That is what he is, a 4th starter in the MLB rotation and that what should be expected from him.

  • Wobbit

    great work, Rob. I now know a lot more than I ever would have known. While reading the article, I felt my anger toward the coaching staff rise up. Let’s not forget that Taijuan is still a young man playing in NYC and therefore in need of the wiser, more objective minds that are paid to provide it. Another failure for Luis Rojas (and maybe Sandy Alderson).

    But I believe his decline was a combination of all these factors. When it started to unravel, cooler heads could have stepped up and adjusted, but the Mets were too desperate as a team, and they badly needed Walker to maintain his incredible first half effectiveness. Hardly an environment to work through career highs and rule changes.

    The short story is, TWalk is a stud who could settle in at #3 and be great… hopefully Buck will help, as will reasonable expectations. I’m all in on TWalk: 165 IP/ 3.45 ERA/ 1.25 WHIP/ 10-6 WL

  • ChrisF

    Great read. I bet if we looked across baseball, we would see SR drop quite a bot for many pitchers. Word on the street is that 100% of pitchers were using advanced tacky stuff. Jerry Blevins commented on it extensively on the SNY Mets podcast.

    I’m sure it changed the landscape for those more reliant on it than others.

  • TexasGusCC

    My kudos also Rob for a nicely presented piece. Seems Walker should take some time this winter between his digital memorabilia sales to try to break this down. Although, it’s probably more Hefner’s job to do it and give it to him, I hope Walker takes the time to study his own stats. I wonder how many of these guys actually do.

  • Metsense

    I can’t wait to read your next article and analysis on the first nine starts compared to the last nine start of Tylor Megill !

  • Rob Rogan

    Thanks, all! It’ll definitely be interesting to see where Walker and the new Mets coaching staff go next season. He clearly has the talent to dominate, but when he goes off the rails he seems to go off them hard. Is that on the player? The coaches? Both? I wonder if deGrom and Scherzer couldn’t impart some advice on maintaining consistency and course correction to Mr. Walker…

  • JimmyP

    Respectfully, I personally find a lot of this type of analysis to be more “effect” than “cause.”

    Staring at numbers trying to discern “meaning.”

    For example: I think people can fall all over themselves “analyzing” — a big word for what folks are actually doing — Lugo’s subpar performance in 2021. But in my mind — and I could always be wrong! always and often! — a lot of it was driven by the fact that his arm wasn’t right, hanging by a thread, doesn’t feel so swell.

    On Lugo: What a difference it could make in 2022 if he’s fully healthy compared to, say, the guy who I think might be physically falling apart. Not too long ago he looked like possibly the best reliever in the NL. Last year he was constantly “not available” for games (putting stress on the entire bullpen in a cascade effect) and unable to give the Mets two innings. And even when he did appear — when all the cushions were in place, he was rested and everything was just so — he still lacked zip and bite and “stuff.” You could see it with your own eyes.

    Right? We all saw it, didn’t we? He wasn’t the same guy.

    Anything the data tells us after that will only be noise — not signal — and utterly meaningless.

    I hope that Walker’s arm was toast in the second half. It sure seemed that way to me. His stuff isn’t amazing even in the best of circumstances, but I like him as a #4 if he’s healthy. He *might* be one of those guys who just doesn’t have that kind of arm. My fingers are crossed because I really do like the way he carries himself on and off the field (in interviews). I did read some lengthy articles on the Super Tack effect, very early into it, and I recall that he was identified as a guy who would be more affected than most.

    Another thought is that — hey, wow, MAYBE Dom Smith really did have an aching wrist all season long. We can pull apart all the data, analyze the hell out of every detail — how he hit curves, what he did against the high fastball, the poor quality of his diet, and so on, endlessly — but it might all be driven by the pure fact that his wrist lacked snap and it messed with his mechanics and the guy got depressed & lost confidence. (That’s the hopeful dream on Dom, but I’m using it to make the larger point that I think we’re still in the 1980s in many respects, still in awe of our big, fact Elias books that tell us Player X hits better on cloudy Wednesday afternoons). The signal and noise problem. Today we have SO MUCH DATA and it’s easy to get lost in it.

    Even when the numbers line up, it’s not always the numbers that are driving the wheel.

    Editor’s Note – Please do not capitalize words in your post.

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