After watching Zack Wheeler head to the Philadelphia Phillies via free agency, New York Mets general manager Brodie Van Wagenen decided to bolster the starting rotation by signing both Michael Wacha and Rick Porcello to one-year deals. On the surface, this certainly seems like a downgrade, especially when looking at 2019 fWAR totals.
On his own, Wheeler produced a career-high 4.7 fWAR this past season, which was his second straight season of at least 4.0 fWAR. Wacha and Porcello each struggled in 2019, combining to post 1.6 fWAR. And while no team can have enough pitching depth, the Mets will have to make a decision on which five hurlers will take up residence in the Opening Day rotation if all six of their current starters remain healthy throughout Spring Training (a big if, of course).
Wacha posted a career-low -0.2 fWAR this past season, which included an 18.5% strikeout rate, 9.8% walk rate, and a 4.76 ERA with a 5.08 SIERA in 126.2 innings of work. He also racked up a handful of relief appearances with the St. Louis Cardinals as he bounced back and forth between the bullpen and rotation. Not exactly the best platform year heading into free agency, making it an easy decision to take an incentive-laden deal to rebuild his value for next winter.
This will be one of a handful of projects for new pitching coach Jeremy Hefner to tackle during his first year back with the organization. In pursuing a project like this, it’ll be important to look back at the right-hander’s recent performances to see if there are any positive things to build upon moving forward.
When looking at Wacha’s first- and second-half splits, it appears that he had a much better second half (3.58 ERA) than he did first half (5.54 ERA). But if we break it down a little more, most of his second-half success came in the month of September, as his monthly ERA numbers between July and September were as follows: 4.26, 4.81, and 2.70. The right-hander’s strong finish to the season consisted of just 16.2 innings across five starts (he reached five innings in a start only once), so it’s not as if he completely dominated down the stretch. But it was a stark difference to his first five months.
Through action on August 31st, his ERA stood at 5.07 in 110 innings. While his SIERA didn’t change much (5.07 through August 31st and 4.89 from September 1st to end of year), something had to have happened in order for this increase in production.
Wacha’s BABIP against went from .305 to .357 between these two periods of time, but it was accompanied with an improved walk rate (10.0% to 8.1%), strand rate (77.5% to 86.5%), and homers allowed per nine innings rate (2.05 to 0.54). Although he watched his strikeout rate go from 19.3% down to 13.5%, he found success by improving parts of his batted-ball profile quite a bit:
It’s easy to see how that homer rate took a nosedive over the season’s final month. Whether these changes are backed up with other facts and changes or not doesn’t hide the fact that the sample size is incredibly small and the results should be taken with a grain of salt. However, it is worth noting that there was a very noticeable shift in Wacha’s pitch mix when taking a peek at his changeup usage.
Through August 31st, he was tossing that offering at a 22.5% clip, but finished the final month throwing it 31.9% of the time. That’s a significant data point because based on pitch value (via FanGraphs), Wacha’s changeup has easily been his most valuable pitch each of the last two years (2.03 and 1.89, respectively, in ’18 and ’19 when evaluated on a per-100-pitch basis). Looking back on this pitch’s performance in 2019 specifically, it was the only one in Wacha’s arsenal that produced an opponent wRC+ below 123 (it was 60), and the 34.4% strikeout rate was far-and-away the highest (next-highest was 14.0% from his four-seamer).
Similar to when we were talking about Porcello’s pitch mix, looking at how things changed in a small period of time for Wacha doesn’t simply mean he should ramp up his changeup usage. However, it has consistently been one of his top-performing pitches with regard to opponent wRC+ and strikeout rate. So it wouldn’t be a bad idea to continue limiting four-seamer usage (where his average velocity has decreased in recent years) and lean a little more heavily on secondary pitches.
Either way, it sounds like Wacha is coming in motivated to prove his worth as a starter, and while that could create some tough decisions for the Mets, it’ll benefit them greatly if the former first-rounder can greatly outperform the contract he signed in December.
