Frankie Montas Has Rekindled an Old Friendship

After a disappointing 2020, Frankie Montas has had a nice bounce-back season. Following a breakout 2019 that saw him post strikeout and walk rates of 26.1% and 5.8%, respectively, and accumulate 2.9 WAR in just 96 innings (his season was cut short due to a PED suspension), Montas regressed heavily last year. His walk rate increased to 9.7%, while his strikeout rate dipped to 25.3%. Even while calling the Coliseum and its expansive outfield home, he posted a 1.70 HR/9 compared to just 0.75 in 2019. The end results were unseemly: he finished 2020 with a 5.60 ERA and a 4.74 FIP, an especially unimpressive figure given his home ballpark.

All the gains he made in 2019 were seemingly lost and at the start of 2021 not much appeared to be different. Montas was sitting on a 6.20 ERA at the end of April with a .369 wOBA allowed, a subpar strikeout rate (21.9%), and a walk rate (6.1%) that was only a slight improvement over the previous season. But early struggles masked a marked improvement from 2020. Much of that bloated ERA was attributable to a brutal start against the Dodgers on April 5 that lasted only 2.1 innings and included seven runs allowed (in fairness, Montas was coming off a finger injury sustained in a spring training start). He had one more disastrous start that month — an April 21 tilt versus the Twins during which he allowed six runs in four innings — but with those two stinkers in the rearview, Montas’ run suppression prowess has been on the mend. Indeed, besides those early hiccups, Montas has only had one start in which he has given up more than six runs (a June 21 start against Texas):

Through 23 starts and 131 innings, his ERA, FIP, and xFIP have all massively improved over 2020, placing at 3.98, 3.47, and 3.65, respectively. His strikeout and walk rates are back to 2019 levels (26.4% and 6.5%) as is his accumulation of WAR (2.5 as of this writing). In the last month alone, Montas has made five starts and pitched to a 2.64 ERA and 2.24 FIP, with a gaudy 35.3% strikeout rate; he’s been worth just over a win. Along with the steady performance of Chris Bassitt (be sure to check out Owen McGrattan’s excellent profile on Bassitt) and a career-best season from Sean Manaea, Montas is leading the way for the Athletics as they simultaneously try to hold onto their Wild Card spot and chase down the Astros for the AL West crown.

A sizable part of Montas’ bounce back has been a reversion to a more successful pitch formula:

Frankie Montas Pitch Breakdown
Season FF% FS% SI% SL%
2019 18.8 18.0 38.4 24.8
2020 24.0 12.9 38.1 25.1
2021 28.5 21.5 31.0 19.0
SOURCE: Baseball Savant

Of note is the reemphasis on his splitter, a pitch he used to great effect in 2019 but that seemed to fall out of favor in ’20, when its usage decreased by almost one third. Coming into this season, Montas made a point of reincorporating his best weapon into his arsenal, as Martín Gallegos captured in his piece on Montas during spring training. Montas said he was too reliant on his two-seamer and had become too focused on his fastball-slider combination at the expense of his splitter, a pitch that he noted was the key to his 2019 dominance. Given the pitch’s success across each of the last three seasons, it’s puzzling that he went away from the splitter in the first place. Leveraging it again has been a boon to his performance.

Frankie Montas’ Splitter Performance
Season Swing% Zone% Chase% SwStr%
2019 55.1 35.4 39.6 22.0
2020 52.5 40.7 44.4 26.3
2021 50.2 29.0 38.7 26.4
SOURCE: Baseball Savant

Those are elite swinging strike rates and become even more impressive when you account for the fact that Montas rarely throws his splitter in the strike zone. The league-average chase and swinging strike rates for the splitter are 37.4% and 19.4%, respectively; Montas has easily paced those benchmarks in each of the last three seasons. That makes the dip in usage last year even more puzzling; as he struggled to punch out batters, you would think he might have tried to make a corresponding adjustment, but his use of the pitch oscillated throughout the year with no apparent pattern:

The difference in Montas’ splitter usage is even more apparent when you filter the data to only include two-strike pitches:

Frankie Montas Two-Strike Splitter Pitch%
Season Pitch%
2019 28.3
2020 14.8
2021 32.8
SOURCE: Baseball Savant

Montas’ use of the splitter has more than doubled this season when he reaches two strikes. We can reasonably assume his gain in strikeouts is at least partially a manifestation of this change. Montas’ put-away rate (the percentage of two-strike pitches resulting in a strikeout) has actually decreased this season compared to 2020 (25.6% to 24.4%), but the increased reliance on the splitter in these counts has bolstered his strikeout rate nevertheless. As the season has progressed, Montas seems to have become more and more comfortable with the pitch, perhaps realizing that its potency is paramount in shutting down the opposition:

I alluded to Montas’ recent torrid stretch, and it perfectly coincides with the rising utilization of his splitter. Taking his game-by-game splitter usage, strikeout rate, and ERA going back to 2019, there is some relationship when you isolate the former and the latter two measures. His splitter usage explains 17.5% of the variation in his daily ERA totals (in that more splitters correspond to lower ERAs) and 23.5% of his daily strikeout rates.

I’ve focused on the splitter for much of this piece, but it probably goes without saying that Montas’ improvement is also a product of curbing his ridiculous home run rate from 2020. That 1.7 HR/9 was unlikely to persist and sure enough it has trickled down to 1.1 in 2021. Some of this has to do with his HR/FB, which has gone from 17.5% in 2020 to 12.2% this season, a shade below the rest of the league. Montas pitches in Oakland and gets a decent number of groundballs, especially with his sinker, so living just below the major-league mean in HR/FB and HR/9 (1.23) seems like a reasonable assumption for the near future. Expecting his 2019 output (0.75 HR/9) and that rate of WAR accrual might be difficult, but replicating that season’s levels of strikeouts and walks is realistic if he continues to use his splitter like he has going forward. And by giving up a normal rate of home runs allowed, this version of Frankie Montas should be one that persists.

Montas’ whiff rates on each individual pitch have remained relatively stable over the past several seasons, meaning the extra strikeouts are a product of his pitch usage and plan of attack as opposed to unstable swing-and-miss rates on any given pitch. It’s another feather in the cap of both Montas and the Athletics organization. It remains unclear why he went away from his best pitch last year, but that season is in the past. Montas has made the necessary adjustment to get back to being the level of pitcher we expected and he should remain a rotation stalwart.





Carmen is a part-time contributor to FanGraphs. An engineer by education and trade, he spends too much of his free time thinking about baseball.

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Dustinmember
2 years ago

He seemed to have trouble keeping his splitter down last year and reduced his usage due to them going out of the yard. You might want to look at his HR numbers on splitters.