The Red Sox, after coming out of the gate hot in April, are starting to show some different holes all over their roster as they cling to first place in the American League East for as long as they can. Their reign atop the division could end, at least for now, as soon as Wednesday night after a loss on Tuesday dropped their lead over the Blue Jays to just a half-game. It was an all-around beatdown in the series opener, but Eduardo Rodriguez’s performance was at the forefront for much of it. This was a strange start for the Red Sox lefty in that the peripherals looked good — he struck out six and walked only one over five innings of work while keeping the ball in the yard all night — but the results were bad, largely due to 11 hits. This has been a trend for Rodriguez this season, and particularly over his last few outings.
If you’re just looking at the peripherals, it has actually been a solid season for the southpaw in 2021. Through eight starts he is striking out over a batter per inning while walking fewer than two per nine and putting up roughly a league-average home run rate. As a result, he’s putting up a really solid 3.27 FIP, which after adjusting for park effects is 19 percent better than lague-average. That park-adjusted FIP puts him in the top 30 in all of baseball.
So that’s all good, but by the results he has very much not been on that level. After giving up five runs over five innings on Tuesday, Rodriguez has watched his ERA climb to 4.70, which would be his worst mark since 2016 and comes in worse than league-average. In terms of difference between ERA and FIP, among the 81 pitchers with at least 40 innings this season only four boast a larger gap. (Nathan Eovaldi is among them.) And as is typically the case when you see a large gap between ERA and FIP, the batting average on balls in play is largely to blame, with Rodriguez allowing a .366 BABIP. That would be 49 points higher than his previous career-high.
When we talk about BABIP, it’s tempting to look at it as just bad luck, particularly when we’re talking about a sample of only eight starts. And to be fair, there is certainly some luck involved. That was the case on Tuesday when a few of the base hits were weakly hit but just found a hole, and it’s been the case all year. In terms of allowing hard contact, Rodriguez has been worse than he was in 2019, but he’s still been a bit better than ever and certainly not bad enough to give up a .366 BABIP. Some of it has been plain bad luck, and there’s also been an element of not getting help from the defense combined with Fenway allowing hits to fall in, as the Red Sox have allowed a .315 BABIP as a team this year, the second-highest mark in baseball.
With all that said, it also wouldn’t be fair to take the burden completely off the shoulders of Rodriguez, because he’s not blameless in this either. There are have been a few issues here as well, and this is in part because he’s not missing bats and he’s throwing more in the zone. Looking at Baseball Savant, his whiff rate has fallen a bit from 27 percent in 2019 to 23 percent this season. As we talk about here from time to time, pitchers can make their own luck by missing bats and not giving batters the chance to benefit from the BABIP gods. Rodriguez is doing that less.
And as you dig deeper, the contact is coming in the zone more. This becomes less surprising when you see that not only is Rodriguez hitting the zone more (51 percent, eight points higher than 2019), but those extra pitches in the zone are coming over the heart of the plate. Below you can see a zone plot of where he’s throwing pitches in the zone compared to 2019, and pay attention to that vertical third of the zone.
It’s not a massive increase, but it’s there and it is making life easier on hitters. And as I mentioned above, they are making more contact on these pitches. Again, we’ll compare 2019 to 2021, this time looking at where batters are swinging and missing on pitches in the zone. Here, you’ll see a distinct lack of whiffs on the inner half to right-handed hitters.
That these lack of whiffs are coming in particular in the zones where righties will do the most damage is significant, because it is righties that are getting the most of these hits against Rodriguez. Over his career he has typically been able to keep even platoon splits, but righties are getting to him this season, particularly when it comes to the BABIP woes. Lefties have a pretty typical BABIP against Rodriguez at .320 — still a bit high, but nothing too extreme — while righties are way up at .378.
And as we shift our focus to what righties are doing, there are two specific pitches I want to take a deeper look at, both featuring similar problems. We’ll start with the changeup, which is the focal point of the lefty’s repertoire and the reason he’s always been able to keep righties in check. This season, righties aren’t necessarily hitting changeups harder off Rodriguez — the average exit velocity is up, but only slightly — but they’re just hitting the ball more often. In 2019 righties had a whiff rate of 36 percent. This season, that number has fallen to 24 percent. This gets back to what we were talking about earlier with making your own luck and not giving them chance to put balls in play and get lucky from there. And again we will compare 2019 to 2021, this time looking only at the changeup and a heat map of where these pitches are typically going.
These two plots aren’t that different, as they are both concentrated in the same corner of the zone. However, in 2019 he did a tremendous job of burying that pitch out of the zone, and there is enough movement that hitters (particularly righties) will go for it and swing right through it. This year, it’s staying in the zone more thanks to a bit less of a vertical drop, and it’s being put into play.
A similar issue is happening with the cutter, although it’s not coming with the same kind of results. Whereas the changeup is getting fewer whiffs but not necessarily a dramatically increased quality of contact, the cutter is actually seeing a few more whiffs in 2019, but when contact is made it’s been much louder, particularly against righties. In 2019, the average exit velocity from righties against the pitch was 88 mph. This year that number is up to 94 mph. The results are a little bit different, but the causes are similar to the changeup as Rodriguez is also struggling to bury the cutter out of the zone as much as he’d like.
Rodriguez is leaving a lot more of these right over the heart of the plate, which explains the heightened exit velocity, and he’s also struggling to consistently get the pitch in on the hands of righties. That’s the easiest way to make this an effective pitch against opposite-handed batters.
So in what has been a bit of a disappointing start for Rodriguez based on the results, there have been a confluence of reasons for the high BABIP and bad results. Some of it has been poor luck, a park that lends itself to more hits, and a defense that is giving up a few extra hits as well. All of those are out of his control. But he can also control his own destiny as well, and if we were to boil it down to one point it would be this: Rodriguez needs to bury his secondaries out of the zone more. It will probably result in his walk rate climbing a bit, but there is room for that to move up a few ticks if it brings his BABIP down to more manageable levels.