Team Chemistry: The Outsized Importance of a Joe Mauer Cold Streak

On Sunday, here at Baseball Prospectus, Meg Rowley wrote a terrific piece about what it's like to be a Mariners fan—specifically a Felix fan—in the later stages of the King's career. Speaking of aging superstars, she wrote “Every franchise has one, because every franchise is peopled by players who age,” and of course she’s right. As a lifelong Twins fan who was 6 years old when they won the ’91 Series (and who could recite the entire 25-man roster of the ’87 team by number as a 2-year-old, according to my dad), I first went through this special kind of grief with Kirby Puckett. Of course, that wasn’t exactly the same situation, as Puckett’s career was derailed by acute and unexpected/bizarre injuries rather than a slow decline, but the hope—hope of recovery from the broken jaw, hope that the vision problems weren’t serious—is the same, I think.

Now the next generation of Twins fans is going through this process with Joe Mauer, and it falls somewhere between the Felix decline and the Puckett abrupt end. Although it may have begun to some degree in 2011, when he hit the 60-day disabled list for now-infamous-among-Twins-fans “bilateral leg weakness,” the defining late-career moment for Mauer is of course the concussion he experienced on August 20^th, 2013, which ended his season and forced a move away from catching much earlier in his career than expected.

Looking back on it, there was a certain sense of optimism surrounding Mauer’s recovery process, particularly among stat-savvy fans. While no one doubted the potential for post-concussion effects to short-circuit Mauer’s career, the idea of him not having to be behind the plate 130-some times per year was definitely appealing. To quote BP’s own Aaron Gleeman, writing then for MinnPost, “By moving away from catcher and avoiding the daily physical toll, Mauer should in theory be able to stay healthier, play more games, and increase his offensive output.”

Unfortunately for Mauer, for the Twins, for Twins fans, and for baseball fans in general, it didn’t work out that way. By TAv, 2014 and 2015 were the two worst seasons of Mauer’s career, which combined with his new primary position of first base to lead to the lowest WARP totals of his career (even including his 35-game debut season), 1.4 and 0.1 respectively. In terms of value, the three-time batting champion had a 2015 that ranked third-last among qualified first basemen, ahead of only Ryan Howard (who also is a candidate for this sort of piece) and Logan Morrison.

Looking at Mauer’s top-level stats, it’s not hard to see the collapse in action. He walked less and hit less every year post-concussion. Further, while 2013’s BABIP wasn’t sustainable (his career figure is .343), the BABIP drop is more a symptom than a cause here. This is better seen looking at his batted ball mix. Since the concussion, there’s been a clear transfer of about 10 percent or so of Mauer’s batter balls away from being hard-hit liners or flies to being soft-hit grounders.

The talk in the Twins media over those two years was that even if Mauer wasn’t experiencing any primary concussion symptoms—which he reportedly was not—the injury may have caused just enough of a drop in his reaction time that he wasn’t able to read pitches and square them up as well as he could prior to it, which seems to be borne out by the stats. It became accepted conventional wisdom that Mauer would likely never be what he once was.

It was noteworthy, then, when Mauer announced prior to spring training this year that he had continued to experience intermittent blurred vision throughout 2014 and 2015. Allegedly, he hid this from the front office (though speaking as a fellow native Minnesotan, there’s a chance this was a reflection of our general “don’t worry about me, I’ll be fine” attitude when it comes to health problems). In an effort to adapt to his new reality, he would try batting with sunglasses this year.

Opening Day came, and Mauer did indeed frequently appear at the plate in sunglasses. However, any coverage of improved performance he may have gotten (at least at the national level) was overtaken by the team opening the season with a nine-game losing streak. It went either unnoticed or undernoticed that in April, Mauer pretty much looked like his old self, if not better. He was hitting the ball harder, with the results to prove it—his batted ball profile approximated that of 2013, which in turn brought his BABIP and batting average back to their prior levels, and he was walking more than twice as often as he struck out.

In a season that felt lost before the end of the first month, at least Twins fans could hold on to the hope that Mauer finally might be alright again. Then May happened.

Walks plummeted, strikeouts skyrocketed, and suddenly it was 2014/2015 all over again. The line would look even worse if not for a sudden power surge at the end of the month, when he hit three homers in as many games (in Seattle, of all places). Sure, that’s getting a touch too selective/small-sample-ish, but in either case much of the hope felt at the end of April disappeared from general Twins fandom. However, that may have been a premature reaction. Take a look at the batted ball profile.

Note that Mauer’s hard-hit percentage stayed at the 2013 level, and the LD/FB/GB split didn’t really change significantly. Although there was a large shift from medium-hit balls to soft-hit, the overall change can’t explain a 60-point BABIP drop.

The biggest change, of course, was on balls not in play. Looking for a possible reason for the dramatic change in both strikeout and walk rate, I went digging through both Mauer’s player page here and his player card at Brooks Baseball. His whiff rate increased dramatically on both hard and breaking pitches, but stayed the same for off-speed offerings. He also saw more pitches in the strike zone in May than in April (across all pitch types).

Unfortunately, there’s no smoking gun to explain these changes. I looked at the average fastball velocity he saw for each of the two months, and it actually dropped from 93.7 to 92.5 mph. I wondered if he possibly just faced better pitchers in May than in April, so I pulled the cumulative season-long stats for opposing pitchers in each month (where cFIP and DRA are weighted by each pitcher’s total IP, but not by the times they pitched to Mauer). The May pitchers were a touch better, but I don’t think enough to make such a huge difference.

I went into this piece hoping to draw a conclusion about which month’s performance I thought would be more likely to exemplify the rest of Mauer’s season, but as is often the case with research, the answer was unclear and messy, which is what led me to the Felix comparison from the beginning of this.

We talk sometimes about where a team is on the win curve—a win being “worth” more to a team that is in the mid-80s, for example, than a team in the mid-60s. That idea applies to Mauer’s career right now. By the end of his age-30 season, in 2013, he was over 48 WARP for his career, and at about 45 bWAR. That’s as a catcher, and even more impressively as a catcher with a variety of hardware and black ink on his page. That likely put him within 10 or 15 wins of serious Hall of Fame consideration, and within 20 of a sure case. All he had to do was have Melvin Mora’s 30s, or B.J. Surhoff’s, or Placido Polanco’s, or Johnny Damon’s. He still could, which is what makes months like April so exciting, offering the promise that this fantastic career will be elevated to what we once foresaw. Every month like May is, correspondingly, a slug to the gut.