How Much Does Throwing Fewer Sinkers Really Help?

Every now and then, I need to refresh my memory on what the baseline stats are for various pitch types, and that brings me back to this piece on pitch type performance from fellow RotoGrapher Alex Chamberlain. I am not only reminded of how inferior sinkers generally are at inducing whiffs and preventing hits on balls in play, but of Alex’s advice to pitchers: “Seriously, don’t throw a sinker.”

But, of course, lots of big league pitchers do, and 33 of them threw at least 500 sinkers in 2019. Given that pitchers stand to give up fewer hits if they switched from their sinker to another offering — assuming their version of that alternative pitch was at least decent — it seems like pitchers who ditch or de-emphasize their sinker should get more attention for doing just that. It also would seem that more pitchers would make that change. In every year of the 2010s, there were no more than 10 pitchers in a given season who decreased their sinker usage by 10 percentage points or more (and also threw at least 100 innings both the current and previous seasons).

Could it be that we have been somehow mistaken about the impact of throwing fewer sinkers? I am taking a first pass at answering this question by looking at the nine pitchers with at least a 10 percentage point decrease in their sinker usage rate in 2019. I am using the pitch usage data from Pitch Info and including only the pitchers who threw at least 100 innings in both 2018 and 2019. Here are those nine pitchers and their sinker usage rates from the last two seasons.

In the table below, I compared the SwStr% that each pitcher had with their sinker in 2018 with the SwStr% of the pitch for which they increased their usage the most last season. The cases of Cashner and Giolito are particularly interesting in that both pitchers essentially ditched their sinkers, leaving themselves room to increase their usage of two pitches substantially. Cashner not only increased his four-seam fastball usage by more than 20 percentage points, but he also upped his changeup usage by nearly 15 percentage points. I used the SwStr% from Cashner’s four-seamer for the table, and with a 6.9 percent SwStr%, it represented a substantial upgrade over a particularly hittable sinker. However, he got swings and misses on 15.5 percent of his changeups. Cashner’s 17.0 percent strikeout rate was still subpar, but much better than the 14.5 and 12.2 percent marks from the previous two seasons. Even as a starter, he showed improvement with a 16.1 percent K%.

By ceasing to throw a sinker, Giolito’s four-seamer and changeup both got a windfall in usage. This paid even bigger dividends for him than it it did for Cashner, as both pitches were better than Cashner’s versions for swinging strikes. Like Cashner and Giolito, each of the pitchers with the next four largest decreases in sinker usage (Lynn, Leake, Lucchesi and Buehler) used their four-seam fastballs as their main substitute pitch. The swap worked out well for Lynn, as his four-seamer had the highest SwStr% (14.1 percent) by far out of the six pitchers whose four-seamers had the largest usage increases in their respective arsenals.

Swapping out sinkers for more four-seamers resulted in a wash for Leake and Lucchesi, as neither of them had a four-seam fastball that was more than marginally better than their sinker for swinging strikes. In terms of SwStr% the change in pitch mix appeared to serve Buehler well, and that was even in light of getting swinging strikes at a relatively robust 7.5 percent rate on his sinker in 2018. As a result, he boosted his strikeout rate from 27.9 to 29.2 percent, but he still added more than half a run to his ERA. Some of that was due to regression from a 78.4 percent strand rate, but his cutter was also a worse pitch for inducing grounders and limiting line drives. Overall, though, foregoing sinkers in favor of more four-seamers appears to be a sound move, especially if a pitcher has at least an average four-seamer for SwStr%.

Bailey and Morton substituted even better pitches for swinging strikes for their sinkers, and it paid off for both pitchers. While Morton’s ERA remained in the lower 3.00s, an improved SwStr%, along with lower walk and home run rates, helped him to withstand regression from a 79.6 percent strand rate. Substituting curveballs for sinkers did not work out for Cahill. Had his curveball been as effective as it had been in previous seasons, his results would have been a lot better, but it was a distinctly below-average pitch for swinging strikes in 2019. Also, while Cahill decreased his sinker usage, it was still his most-used pitch. His sinker got rocked for an average exit velocity on flyballs and line drives of 99.0 mph (as compared to 94.3 mph in 2018), and he allowed nine home runs on the pitch after giving up only two the year before in his bounceback season with the Athletics.

If there is news this spring about a pitcher throwing fewer sinkers, it is probably cause for celebration, but only if that pitcher has a good four-seam fastball or secondary pitch. As of this writing, there is no specific mention of any pitcher making that change in Jason Collette’s annual new pitch tracker. One change that did catch my attention was Brad Keller adding a curveball. In both of his major league seasons, Keller has thrown a sinker for roughly one out of every four pitches, so maybe his new curveball will come at his sinker’s expense. Especially since Keller’s sinker was a much worse pitch in 2019 than it was in 2018 — getting fewer whiffs, chases and grounders — he may look for a reason to use it less.