Jose Quintana’s Increased Sinker Usage Might Be Hurting Curveball

Jose Quintana owns an underwhelming 5.24 scFIP (Statcast FIP) and 6.00 ERA in August. This, of course, is not what the front office had in mind when they gave up their two prized prospects, Eloy Jimenez and Dylan Cease. So what’s the deal with the new Cubs pitcher?

Quintana’s struggles coincide with a drastic shift in pitch selection. Whether that is directly causing the increase in runs allowed is impossible to know, but, in theory, the change in his repertoire is indeed hurting the pitcher.

Quintana now throws mostly sinkers

At the start of August, Quintana became a sinker-ball pitcher, forgoing his typical 40 percent four-seamer usage in favor of the sinker.

Since the southpaw became a sinker-first pitcher, his four-seamer has induced 38 percent fewer whiffs. Maybe the decrease in whiffs suggests Quintana isn’t feeling comfortable with the pitch, causing him to throw more sinkers instead.

Quintana’s curveball is not as good since he started throwing more sinkers

Q has made a career of striking out batters and inducing weak contact with the hook, so he’s only going to be as good as his curve is. But now that the 28-year-old’s primary fastball is a sinker, his curve has suffered mightily.

Batters are crushing what had previously been Quintana’s best pitch. Rather than making batters whiff against roughly 15 percent of his curves, the lefty has given up around 25 percent more contact against when spinning the bender.

Not only have batters made more contact against Q’s curve, but they’re making more hard contact, which has contributed to a shocking .625 slugging percentage against the pitch.

Quintana’s curveball is better disguised when throwing four-seamers

I think Quintana’s broken curve could be a consequence of throwing principally sinkers. Batters might be able to differentiate between his curve and sinker more easily than they can the curve and four-seamer. Take, for example, the below release-point graph in which Q’s four-seamer and curve horizontal release overlap one another.

In contrast, the lefty’s sinker release point is noticeably different from both his sinker and curve.

Final thoughts

Quintana decided that throwing more sinkers would get him more outs, specifially grounders. That hasn’t worked. Right when Q started throwing more sinkers, his curve started getting barreled up more often. Perhaps this is because batters are quickly identifying curves out of the hand. The release-point variance between curve and sinker is greater than between the breaking ball and four-seam.

So is “fixing” him a matter of getting away from the reliance on the sinker or making some other mechanical changes? Only time will tell, but it’s definitely something to keep an eye on moving forward.