Based on last year’s performance and this year’s early-season improvements, it wasn’t hard to project Addison Russell as a 5+ WAR shortstop. After all, he was coming off of a .316 wOBA and 3.9 fWAR. And the one knock on his game, contact, began to dissipate after he nearly finished 2016 with a league average contact rate. That trend continued through this April and he even began to show signs of significantly better plate discipline by swinging at 25 percent fewer pitches outside the zone.
But since shoulder pain surfaced in late April or early May, the promising shortstop’s game dramatically suffered, and now he’s on pace to barely produce a single win more than a replacement player by season’s end.
So what happened? Russell’s struggles are multifaceted, but for the sake of this piece we’ll just talk about two glaring issues: 1) trouble with breaking pitches and 2) possible residual effects of a shoulder injury.
Trouble with breaking pitches
Russell was able to combat sliders in 2016 by producing roughly league average value against them (0.09 wSL/C). This was impressive for a young hitter, especially since he saw a slider once every five pitches. He did, however, struggle against curveballs (-2.02 wCB/c), but only saw them once every 13 pitches. Safe to say he was able to handle breaking pitches.
But something happened between then and now and pitchers have begun to approach Russell differently. They’re throwing 12 percent more breaking pitches, most of which have been curves (2016: 8%; 2017: 13%), which we’ve just established were his weak point last year.
Russell hasn’t been able to combat the increase in breaking pitches. While he produced the same amount of runs against sliders as most other players, he’s now 4.23 runs below average against the pitch. Granted, he’s been able to generate league average runs against curves (0.32 wCB/c), but he’s producing fewer runs against breaking pitches in total.
Possible residual effects of shoulder injury
I hate to speculate, but I’m fairly convinced that Russell is dealing with the lingering effects of the shoulder pain he experienced about a month ago. He admitted that the problem surfaced before the Cubs actually sat him. With that in mind, it’s entirely possible that he’s continuing to play through discomfort. Or maybe the consequences of shoulder pain (e.g., muscle instability in muscles associated with kinetic chain) are prohibiting him from reaching his potential.
I hope I’m wrong, but it just seems to me like more than coincidence that he hasn’t been able to throw or hit a baseball very well since we heard of the shoulder problems. The counter against this argument is that surely the Cubs are smart enough to sit him. Issues like these can sometimes slip through the cracks, though. Even Jason Heyward played through wrist pain last year without telling the staff.
Russell said he experienced shoulder pain about a week before the Cubs began to sit him on May 10. This admittance makes for a rough, yet still suitable, timeline for comparison. Let’s say he began experiencing pain a week prior to being scratched from the lineup. Before then, he was batting .260 with a .140 ISO and .306 wOBA. After May 3, he has hit for only a .154 average, .115 ISO, and .251 wOBA. Both samples are still small and don’t tell the whole picture, however, meaning we need to look at more of the rough data.
Batted-ball types also paint a picture of a damaged player. About 43 percent of Russell’s batted balls were flies prior to May 3, while only 28 percent have been since then. Such a large decrease in pitches smacked in the air explains why he’s only at a .251 wOBA. He simply hasn’t hit that many pitches to the parts of the park associated with extra-base knocks.
It’s more than just the product, though, as some of Russell’s swings have looked downright odd. For instance, take the one below from Sunday’s game against the Cardinals. Of course, he could’ve just been fooled on the pitch and was swinging to protect. It’s also possible I’m trying to find little pieces of anecdotal evidence to confirm my suspicion.
I know I can’t prove that the Cubs shortstop is dealing with some consequence of a recent shoulder injury, but I don’t think it’s out of the realm of possibility either. Bryce Harper’s shoulder problems bugged him all of last year, eventually leading to a reduced .342 wOBA after hitting the league away to an MVP campaign in 2015. It may not be the pain that’s causing the problem, but the causative agents of it (e.g., mechanics, instable regions, etc.). For those reasons, I’m concerned.