In his Major League debut for the Mets, 23-year-old Zack Wheeler struck out seven hitters in his six innings of work. Of those seven strikeouts, six came on fastballs — and of those six, four came on whiffs induced by fastballs.
This got me wondering, what pitchers this year have generated the largest percentage of their strikeouts off of their fastball? And how many generated those strike outs on swings and misses on fastballs*?
Yu Darvish had arguably the most impressive fastball-induced strikeout performance this season during his May 5 start against the Red Sox. Darvish struck out 14 batters (which he’s done three times this season), six (43%) of which came on fastballs. And each of those six came came on a whiff induced by that fastball.
The pitcher with the highest single-game strikeout total where each strikeout came on a fastball? That would be the Cardinals’ Shelby Miller. Miller struck out 13 Rockies (walking none, by the way) over nine innings on May 10th, all coming on fastballs (nine looking, four swinging). No other pitcher has recorded a double-digit strikeout game with each strikeout coming via the fastball. The next highest number of strikeouts with 100% via fastballs and at least 75% via whiffs belongs to King Felix — eight on May 19th against the Indians.
The highest single-game strikeout total with each strikeout coming on a whiff-inducing fastball? There were five of them. Ross Detwiler, John Lackey, Lance Lynn, Jose Quintana, and Luke Hochevar each recorded five swinging strikeouts — all on fastballs — this season.
What about season totals?
Max Scherzer (116) and Matt Harvey (115) are second and third respectively in terms of total strikeouts across the league, and coincidentally the percent of their strikeouts coming on fastballs are also about even (47% and 45%). The one noticeable difference? Harvey generates swinging strikeouts on those fastball-induced punch outs 67% of the time, compared to 57% for Scherzer.
For pitchers with more than 600 fastballs thrown the largest fastball strikeout percentage goes to Tony Cingrani at 90%, with 57% of those coming on whiffs. Now, Cingrani only as 52 strikeouts for the year, but when he does get one is almost always on a fastball.
Luis Mendoza, however, takes the cake when it comes to strike threes on fastball whiffs — 88%, 11% higher than the next closest pitcher Jose Quintana). Now, the majority of Luis’ strikeouts come on non-fastballs (81%), but he makes those fastballs count.
None of this is to say that pitchers that induce strike threes on their fastballs (especially swinging strike threes) have better fastballs. There’s a lot more that goes into an evaluation than what I’ve shown here. This is really more for funsies.
*For this study, fastballs includes four-seamers, two-seamers, cutters, and sinkers. Split-fingered fastballs were not included.
Data based on starts through June 20, 2013