Ranger Suárez Is Losing One of His Favorite Weapons on the Mound

The Boston Red Sox are 5-1 in the six starts since Ranger Suarez returned from the injured list on July 26. In his last three starts, he has started to increase his pitch volume to more than 80. Amid the adjustments during these outings, Suárez has seen his strikeout rate drop by 8.4%, while walks have increased by 2.7%. That lack of strikeouts and the increase in on-base percentage have pushed his FIP to 4.61 during this stretch, well above the 3.25 he recorded in his 17 starts before going on the injured list.

Opposing hitters are taking advantage by attacking him more in the strike zone and have improved contact by a slight 3.3%. They are also chasing more (11.1%), due to the mix of his secondary pitches, the cutter, changeup, and curveball. However, there is a problem Suárez has to solve, and it does not exactly correspond to his return: his inconsistency with the sinker.

Since last June, Suárez has been using his sinker much more against left-handed hitters. The results we see in this summary are general and show the combined adjustment of both profiles against his sinker. More contact, more power, and fewer swings and misses.

The PutAway% from this last month gives us a preview that Suárez has stopped using the sinker as a weapon to finish his most important counts. Since returning from the injured list, the xwOBA has skyrocketed to another level. All of that is clear. But the big difference here is not being made by right-handed hitters. It is left-handed hitters who are getting most of the quality at-bats against Suárez.

And that is not the worst part. Over the last four seasons, that trend has continued to increase against the sinker.

This comparison better contextualizes the situation. The expected metrics remain in a similar range, but BABIP has skyrocketed from a not very consistent .298 to a dangerous .375. Suárez has stopped striking hitters out and getting swings and misses at a concerning rate this year, while hitters have made a small jump in the quality of their contact.

Run Value/100 pitches probably summarizes it better, taking each of those situations into account. In 2021, the season when the sinker looked like the best pitch in his arsenal, Suárez recorded 2.6 RV/100 with a .202 xBA allowed. Last year, it dropped to -0.3, and this year he is at -0.2, with a .312 xBA, the highest since 2020.

That said, let’s look at the next part of the problem: where he throws his sinker and how the opposition is responding.

Here we have the 2026 stretch (chart on the left) vs. 2023-2026 when he throws his sinker against left-handed hitters. I don’t think it is difficult to notice where Suárez is having problems: pitches located in the vertical middle part toward the inside of the strike zone.

Hitters are destroying his sinker inside because of two key problems: he lost velocity and lateral movement, two characteristics that made it a more difficult pitch to decipher.

In 2026, his sinker is averaging just 90.3 mph, and 89.9 since he returned from the injured list. On the other hand, he lost more than two inches of horizontal break toward the hitter’s hands, dropping from 16.0" between 2021-2023 to 13.8" this year, below average. Added to that loss of bite is greater induced vertical break (6.2" IVB), which takes away depth from the “sinking” action.

The result of what might look like a slight loss in velocity and break is making a big difference in favor of the hitters, who are taking advantage of the sinker, which now stays in the strike zone for longer periods of time.

Ranger Suárez’s next start will be against the Yankees, and it'll be fascinating to see if he tries to buck this recent trend. If he continues to take pressure off the sinker in key situations, he will have to find another way to compensate for it. For the Red Sox, the best news would be for his adjustments to begin giving him the necessary turn to bring back the best version of his arsenal.