Blue Jays’ Kevin Gausman, Athletics’ Frankie Montas Throw MLB’s Best Splitters

Today, the MLB Best Pitches series continues with cutters and splitters. Last week, the series began with changeups and curveballs.

We’re going pitch by pitch through the arsenals of all starting pitchers who threw 135 or more innings last season to determine the game’s best – and worst – offerings. The main inputs are pitchers’ bat-missing and contact management results. Each pitch is compared to league average swing-and-miss rates and pitch-specific Adjusted Contact Scores.

Adjusted Contact Score is, on a scale where 100 equals MLB average and the lower the number the better, the relative production a pitcher “should have” allowed based on the exit speed/launch angle mix of every batted ball yielded. An average pitch gets a “B’”, and a sliding scale is applied to each pitcher’s results to approximate a bell curve.

Cutters/splitters as a tandem finished fourth behind changeups, sliders and curves in terms of effectiveness. They finished behind those three both in terms of Adjusted Contact Score (95.2) and swing-and-miss percentage (12.1%). 24 pitchers met the total pitches/batted ball qualification criteria for their cutters, 7 for their splitters. Marcus Stroman and Nathan Eovaldi did so for both their cutters and splitters. The six pitchers below (two for their cutters, four for their splitters) received “A+” or “A” grades. The Brewers’ Corbin Burnes is not among that group. He got a “B+” for his cutter, but deserves special mention. He threw his cutter an amazing 52.3% of the time, way more than any other qualifying hurler threw their cutter or splitter. Its 95.1 mph velocity and 2767 rpm spin rate both easily exceeded any other qualifying cutter. If I separated cutters and splitters and graded them independently, he’d likely have received at least an “A”.

RHP Kevin Gausman – A+ – (78 Adj. Contact Score, 24.8% Whiff Rate) – Gausman took his out pitch splitter from San Francisco to Toronto this offseason. His pitch-specific Adjusted Contact Score tied for 5th among qualifiers, and his swing-and-miss rate was 2nd. He used it as a grounder-generator – his 50.3% grounder rate easily exceeded the cutter/splitter average of 39.4%. He also muted fly ball authority, with a pitch-specific Adjusted Fly Ball Contact Score of 78.

Gausman threw his splitter 35.3% of the time, the 4th highest cutter/splitter usage rate among qualifiers. Its velocity (83.7 mph) was slightly below average, as was its vertical movement (0.4 in.) Its spin rate (1526 rpm) was in the average range for a splitter, while its horizontal movement (7.1 in.) was slightly above. His splitter also received an “A+” in 2020, with even better grade components (59 Adjusted Contact Score, 25.9% swing-and-miss rate).

RHP Frankie Montas – A+ – (78 Adj. Contact Score, 25.8% Whiff Rate) – Montas’ splitter’s statistical measurables almost exactly match Gausman’s. They tied for 5th among qualifiers in Adjusted Contact Score, with Montas taking the top spot in swing-and-miss rate. Montas’ pitch-specific grounder rate off 44.0% wasn’t as high as Gausman’s, but the A’s righty stifled grounder authority more successfully (67 Adjusted Grounder Contact Score, 1st among cutter/splitter qualifiers).

Montas threw his splitter much less than Gausman (22.4%), but threw it much harder (87.6 mph) and with more spin (1595 rpm). He also threw it with slightly less horizontal (6.5 in.) and slightly more vertical (1.0 in.) movement than Gausman.

The Other Star Pupils – The other “A+” grade went to Tyler Mahle for his splitter. Mahle’s pitch-specific 64 Adjusted Contact Score tied for the very best among cutters/splitters. His splitter had the most spin (1841 rpm) among qualifiers, and he also posted the best Adjusted Fly Ball Contact Score (41). The other “A” grade splitter belonged to Marcus Stroman. He used the pitch as an extreme grounder generator, posting a 58.4% grounder rate. He was also pretty fortunate to limit hitters to a 14.6% liner rate with his splitter – that’s unlikely to persist moving forward.

The two “A”-grade cutters belonged to Walker Buehler and Luis Garcia. Buehler’s pitch-specific Adjusted Contact Score of 64 tied for 1st among all qualifying cutters/splitters, and his 2619 rpm spin rate ranked 3rd. Buehler posted a strong 46.5% grounder rate with the pitch, and smothered authority across all batted ball types (Adjusted Fly Ball, Liner and Ground Ball Contact Scores of 69, 77 and 64, respectively). Garcia’s swing-and-miss rate of 23.2% was 1st among cutters and 3rd among cutters/splitters combined. He gave up some loud fly ball contact, but did post a 14.6% pop up rate with the pitch, away above the 8.8% average.

Just Missed: 6 pitchers received “B+” grades for their cutters/splitters. We’ve already talked about Burnes’ cutter. In addition, Stroman, Kyle Gibson, Lance Lynn and Tyler Anderson got “B+” grades for their cutters, and Nathan Eovaldi did for his splitter. Burnes is the only one of that group to be well above average both in terms of contact management (80 Adjusted Contact Score) and bat-missing (15.0% whiff rate). His 52.3% usage rate was also by far the highest. Gibson (69 Adjusted Contact Score), Lynn (80), Stroman (83) and Anderson (86) were well above average contact managers, Eovaldi (16.4%) was a big bat-misser.

The Worst Cutters/Splitters: No qualifying cutters or splitters received a grade below “C”. The worst pitch-specific Adjusted Contact Scores belonged to Joe Musgrove and Yusei Kikuchi (both 127), the worst swing-and-miss rates to Eduardo Rodriguez (6.2%) and Ryan Yarbrough (6.5%), all “C” grade recipients.

2020 “A” Grade Recipients: Gausman also got an “A+”’ for his splitter in 2020, while Trevor Bauer and Hyun-Jin Ryu got “A” grades for their cutters. Bauer didn’t qualify in 2021, while Ryu dropped way off to a “C+” in 2021. His pitch-specific Adjusted Contact Score skyrocketed from 47 to 107, while his whiff rate plummeted from 13.5% to 9.3%.

The highest graded cutters tend to be thrown hard with above average spin rates and significant horizontal movement. The best splitters also tend to have higher spin rates, though velocity and horizontal/vertical movement don’t seem to strongly correlate with effectiveness. The way in which the splitter plays off of the pitcher’s fastball appears to be a key factor. Here is a table with all 2021 qualifiers’ cutter and splitter grades.