Red Sox Fill Out Rotation With Intriguing Michael Wacha Addition

The Red Sox have made their first free-agent signing of the offseason, bringing in Michael Wacha on a one-year, $7 million deal, as the Boston Globe’s Alex Speier reported. The 2022 season will see Wacha donning his fourth uniform in the last four years after he spent ’21 with the Rays, ’20 with the Mets, and everything up to that point with the Cardinals. That recent bouncing around comes as his performance has fallen on hard times, with three straight seasons with an ERA over 4.50. But while the 30-year-old righty may not be a splashy signing, teams have found ace-level performance in this price range in previous years, like the Giants signing Kevin Gausman to a $9 million deal in 2019, or the Blue Jays signing Robbie Ray for $8 million last offseason. And in Wacha’s case, there were some interesting things happening with him late in the year that make this deal worth diving into.

When Wacha is off, as has often been the case since 2019, he has a hard time keeping the ball in the yard. His HR/FB rate has nearly doubled from his prime years with the Cardinals and is the fourth worst in the majors since 2019. And that’s despite his velocity — 93.8 mph on his four-seamer on average last year — being nearly the same as it was when he was in St. Louis.

Wacha succeeds or fails with his changeup. It allowed a .270 wOBA last year, and he’s thrown it over a quarter of the time in the last two seasons. It’s his best swing-and-miss pitch, with a SwStr% of 19.6%, though honestly, it’s his only swing-and-miss pitch; his fastball, cutter and curveball get whiffs less than 10% of the time. He throws his change in the upper 80s, about 7 mph off of his fastball, and with its decent arm-side movement plus an average amount of drop, it can be lethal below the knees to lefties. He throws it more than 25% of the time to righties as well, and its effectiveness only slightly drops against them (a .262 wOBA to lefties and .275 to righties).

But even Wacha’s nasty changeup isn’t immune to the long ball; its HR/FB rate last season was 24%, the worst of any of his pitches. Like most changeups, it leads to a lot of ground balls, but last year, it had a career-low GB% (49.5%), career-high FB% (24.8%), and career-high launch angle (8 degrees). A lot of this change in results, though, seems to have come from hitters being in better position to elevate balls in the lower third of the strike zone.

Wacha is not necessarily throwing more changeups in bad locations; in fact, his rate of changeups in the heart of the plate was his lowest since his rookie year. It’s just that more of those balls at the knees are being elevated. If you look at just his changeups thrown in the “shadow zone” — a great place to throw one — you can see that he allowed an average launch angle of 7 degrees, the highest of his career. It’s a sign that his changeup has become easier to elevate, and it could be a result of having more arm-side run than in years past, creating less relative drop.

Beyond his changeup, the real issue for Wacha the last couple years has been his cutter. He’s increased its usage over the last two years, all the way up to 27.2% in 2020 and 24.8% in ’21. But hitters tore it apart last year to the tune of a .415 wOBA allowed, and according to our pitch value metric, it’s been a negative his entire career, with the lone exception being the 2018 season. The difference between now and then is that the cutter drops less and has less glove-side movement but still comes in at the same velocity. That’s not a great recipe for success; the only cutter that was less valuable in 2021 was Martín Pérez’s — the guy Wacha will likely be replacing in Boston’s rotation.

Wacha and the Rays seemed to have concluded that his cutter was a lost cause, because in mid-August, its usage dropped; from August 28 onward, he threw only a small handful. His performance during that cutter-less stretch, you ask? A 2.88 ERA and 3.29 FIP. That’s the stretch that earned him this contract, and it would seem obvious that his cutter will stay missing next season in Boston — or that might be premature, as Wacha stated recently that he plans on bringing it back.

Wacha looked like a completely different pitcher late in the season without his cutter, with its usage distributed to a newly developed sinker and his curveball; both of those pitches went from basically unused to each being thrown more than 10% of the time. The sinker is a logical replacement, given its low spin rate, and the early returns seemed positive, as it allowed a .333 wOBA. It’s hard to draw a sweeping conclusion on it after this limited sample, though, and the same can be said for his curveball, which was hit quite hard (.425 wOBA) in its limited run, though none of that came in the form of extra-base hits, and it had an absurd 71.4% ground-ball rate. It will be interesting to see what kind of arsenal he brings to the table in 2022 after an offseason of tinkering with these pitches and working with a new staff.

Wacha joins a rotation that has a few holes to fill after the departure of Eduardo Rodriguez to the Tigers and Pérez leaving as well (albeit via a declined option). Nathan Eovaldi and the (presumably) healthy Chris Sale will take the first two spots, but the depth gets thin fast after those two. Nick Pivetta, who has never had an ERA under 4.50, and Wacha are the other two who seem to have sure holds on starts. The Sox do have a pair of young arms that impressed last season in Tanner Houck and Garrett Whitlock. The former with his Sale-esque windup feels like a shoe-in considering the 3.68 ERA he provided as a fill-in starter last season in 58.2 innings. That could push Wacha to the bullpen, especially if the Red Sox end up signing another starter this offseason, though adding him takes their estimated payroll to $179 million, which is $14 million shy of last year’s mark.

There may not be a lot of room for Boston to add another starter, especially since the team has shown interest in adding a middle infielder as well. But if the Wacha that was dealing last September is the same guy that the Red Sox just signed, then they may not need much else.