We all know the Red Sox rotation looks incredibly bad on paper, and there are a lot of ways to contextualize that. Nathan Eovaldi, who switched to the bullpen last year after injury and underperformance, is the staff ace. Ryan Weber, who has been a Quad-A journeyman for his career, is the number three. Zack Godley, who fell out of Arizona’s rotation and ended up in Toronto’s bullpen last season, is the number four. They literally don’t have a number five right now. It’s all looking bad. My go-to explanation for what this rotation looks like, though, is that Martín Pérez is the number two.
Pérez was signed by the Red Sox this offseason, and to be fair to them he was not supposed to have this role. At that time, David Price was still in the organization and both Chris Sale and Eduardo Rodriguez were healthy. Things have changed. Still, I was not a big fan of the move mostly because, well, Pérez has generally just never been good. Going back to 2014, he had never had an ERA better than 4.38, he had been coming off of four straight years with a FIP of 4.45 or higher, and by DRA-based WARP he had been below replacement level for each of the last five seasons. Whichever way you slice it, Pérez had a track record. It was just bad.
That said, there was some cautious optimism around the southpaw after he was signed to a one-year deal, largely due to some changes last season. In 2019, his first and only year with the Twins, Pérez started throwing a cutter and made it his most-used pitch for the season. That helped lead to a year in which he allowed some of the most consistently weak contact of any pitcher in the game. Weak contact is good! It also helped him get off to a big start, pitching to a 2.95 ERA over his first 11 starts. The hope was he could refine what made him so good early that year and have it carry over so he doesn’t have another stretch like he did to end 2019 when he pitched to a 6.29 ERA over his final 21 starts.
Personally, I was not ready to buy into the weak contact and the changed approach meaning that he was going to come in and be a big surprise for the Red Sox this year. Weak contact is great and there was some bad luck in his results, but as I’ve said many times pitchers can also make their own luck. And with a guy like Pérez who walks nine percent of the opponents he faces and strikes out batters at a well below-average rate, you set yourself up to be bitten by the BABIP bug. It’s pretty self-explanatory, but when you allow more contact you open yourself to more bad luck opportunities, and that can lead to more runs when you put more runners on base for free.
We are still very early in this season, of course (at least in terms of pure number of games rather than percentage of the season), but the early returns have been solid. Pérez had made three starts thus far this year. Things got off to a brutal start as he allowed five runs in his first two innings, but he finished that outing with three scoreless innings to steady the ship. That was followed up with a solid 5 2⁄3 inning, two-run performance before Wednesday night’s five shutout inning game against the Rays. All told, Pérez has pitched to a 3.45 ERA and the team has won two of his three outings thus far. From that perspective, it is hard to complain.
On the other hand, my concerns about the strikeouts and walks still lurk over everything. He hasn’t exactly been throwing a lot of clean innings, and in fact allowed at least one baserunner in each of his five shutout innings in Tampa Bay. Overall, the lefty has 11 strikeouts and nine walks over 15 2⁄3 innings. Percentage-wise, he has a 16.7 percent strikeout rate and a 13.6 percent walk rate. Again, we’re talking about three starts, but peripherally that’s not what you want.
Still, though, we have to give credit where it’s due and that is where the weak contact comes into play. As I said, that was probably the main reason for optimism heading into the year, and so you can’t brush it aside when it comes true. According to Baseball Savant’s Statcast data, Pérez is once again in the top four percent of the league in average exit velocity, and his hard-hit rate of 22 percent is seven percentage points lower than 2019, too.
What’s particularly interesting isn’t just that he is getting weak contact again, but that he’s actually getting a different kind of weak contact. Pérez has always been a groundball type pitcher with a ground ball rate that has generally sat around 50 percent year in and year out. That has cratered down to just under 38 percent through three starts this year. It would appear a change of approach has helped with this kind of transition, as you can see his fastball and cutter are both being worked up in and above the zone a bit more early this year compared to last season.
This obviously works to change a hitter’s eye level and can make things more difficult on the opponent. If you know you’re getting something down in the zone, it clearly makes your job as a hitter much easier. There has been some tangible results from this early on, too. One might think with a such a decline in ground ball rate that much of it would go to fly balls. His fly ball rate on Baseball Savant has stayed mostly steady with his career norms, though. (We should note that parsing the difference between fly balls, line drives and pop ups can be a bit subjective.) Instead, pop ups have gotten a big boost this year, and for a pitcher if you can’t get a strike out a pop up is the next best thing.
This doesn’t all come with good news, though, because there is still reason to be skeptical here. For one thing, while Pérez has seen an increase in pop ups he’s also seen an increase in line drives, which are the batted balls most often converted into hits. Furthermore, he’s also being barreled up by opponents more often this year. Despite that, he has yet to allow a home run, and with the way the ball seems to be flying around the league this year, that is not something I’d bet on continuing. So, there is some regression coming there.
At the end of the day, I remain skeptical of what Pérez can provide as I just cannot put too much faith in a guy with his kind of strikeout and walk numbers, particularly with the home run luck he’s getting early. That being said, the path to success for him this year was always going to be getting weak contact and avoiding too much bad luck. Early on, after those initial two innings, he’s done exactly that. Whether or not it sticks around will remain to be seen, but the Red Sox will take whatever they can get whenever they can get it with this rotation.