The news of Joe Ryan’s strained left groin at the beginning of this month was by no means a good thing. It meant Ryan would have to miss roughly three weeks with the team. However, it was not all bad news. It offered an explanation, a sigh of relief.
Ryan looked out of sorts starting with a rough outing in Atlanta on June 27th until August 2 against the St. Louis Cardinals. He allowed at least two runs in every game he started en route to an 8.63 ERA and 1.79 WHIP in 32.1 innings. All of this came on the tail of a complete game shut-out against the Boston Red Sox on June 22, where he seemed to have sorted things out after a less-worrying and shorter poor stretch in late May/early June.
Back then, Ryan’s secondaries looked like the appropriate scapegoat for his troubles. He left too many splitters floating and sliders/sweepers hanging for batters to jump on. Pitchers experience setbacks all the time, and I believed Ryan was quickly going to fix his issues. Instead, things became even more strained.
In his second rough stretch, Ryan’s fastball was just as much, if not more, of a culprit than his secondary pitches. Ronald Acuna took Ryan’s first pitch of the game, a fastball, deep to right center, thereby starting the Braves’ onslaught. Ryan also threw Austin Riley a fastball 0-0, and he fouled it straight back, suggesting he was expecting it and/or was timed well for it. Riley spat on Ryan’s splitter on the next pitch before crushing another high fastball for a two-run shot.
Although Maikel Garcia would accomplish the same feat Acuna did on July 3rd, sitting on fastballs did not appear to be a driving factor in Ryan’s slump. That compounded confusion and worry. Ryan also appeared to lose some command of his pitches, like when he floated this 2-2 splitter to Jordan Diaz and this 0-2 slider to Michael Harris II.
Part of those command issues (control in this case) were seen in his Behind%. Failing to get ahead in counts, Ryan fell victim to one of the most explanatory circumstances in pitching. As is widely known, pitching in two-strike counts is more desirable than three-ball counts. Ryan threw 11.8% of his pitches while behind the count between June 27th and August 2nd (his career mark is 8.8%). It may not be a massive difference, but it helps further explain his struggles.
Ryan’s struggles were generally difficult to comprehend. No easily identifiable issue emerged, and he nor the team gave a comprehensive explanation. Ryan was leaving pitches high when he shouldn’t, teams were hitting his fastball, and his secondaries weren’t performing. He was also missing the zone (between June 27th and August 2nd, Ryan pitched in the zone 44.8% of the time compared to a career 48.5% rate) and getting behind in counts. But why? Well, it’s probably because of a bum left groin.
Pitchers use several muscles and joints in their throwing motion. Many of them are in the upper body, but the lower half also plays a significant role. To achieve velocity or to simply throw a baseball off a mound, a pitcher must generate momentum down the slope of the mound. A pitcher’s leg kick and rotation off the mound work together with gravity as the pitcher’s weight is transferred from their back leg toward home plate.
In the pitcher’s left leg, a host of muscles work to decelerate and to stabilize and maintain a desirable amount of knee extension while he rotates his hips and trunk to deliver the baseball. There are a couple of factors in his left lead leg that incentivize a healthy and strong groin/adductors.
First, the energy that is transferred from Ryan’s back leg, harnessed by his front leg, and up through his trunk to his arm and wrist can only be efficiently transferred with a stable front leg. Whatever force is generated toward home plate must be counteracted by the front leg. It essentially “pushes back” and “straightens” while the throwing motion is completed.
Should that front leg fail, a pitcher may “lunge” too much, effectively lowering the pitcher’s body and release point to an abnormal spot while also “blocking” the back leg and trunk as they work to swing around. This inability to effectively “drive” the front leg back results in less energy transferred through the ball, also causing an inconsistent delivery and potentially command issues.
Stride length of the lead leg is also of critical importance to a pitcher’s velocity. As said in this scholarly article, “decreases in stride length lowered velocity whereas increases in stride length increased velocity without affecting accuracy.” Perhaps a pitcher would shorten his stride, knowing it would require more strength to counteract the energy transfer. Adding to that, perhaps that shortened stride would feel abnormal to the pitcher, also contributing to command issues as he tries to relearn that part of the throwing motion.
As Ryan returns to the rotation, we now know things to be wary about. Missing the catcher’s glove once or twice may not mean he’s having trouble stemming from his groin, but long periods of it may sound alarms on this issue.
