Trevor Cahill Trusting His Cutter

It’s hard to remember Trevor Cahill is only 25 years old. After starting 32 games as a 21-year-old, Cahill established himself as a useful major-league starter. Like most 21-year-olds, he was hardly a finished product. Over the last four seasons, Cahill has steadily improved his game, the way most prospects his age might improve in the minors. But because Cahill has done it at the major-league level, he almost seems like a disappointment. That’s not the case, as Cahill has blossomed into an above-average starter. One of the biggest reasons for Cahill’s emergence has been his increasing strikeout rate. Last season, the development of a cutter helped Cahill strike out more hitters, leading to a career-high 3.0 WAR season. If his first three starts this year are any indication, Cahill’s cutter is going to be even more of a weapon this season.

Cahill’s cutter usage has dramatically increased at the start of this season. Per the wonderful BrooksBaseball.net:

Fastball Usage	Cutter LHB	Cutter RHB	4-seam LHB	4-seam RHB	Sinker LHB	Sinker RHB
2012	6%	18%	12%	5%	50%	59%
2013	20%	27%	8%	0%	39%	56%

The above chart shows Cahill’s increased reliance on his cutter against both righties and lefties, though the big jump has been against left-handers. The increased reliance on the pitch has mainly come at the expense of Cahill’s four-seam fastball. Cahill started to eliminate the pitch from his repertoire last season, but has taken it a step further in 2013. That’s not a bad thing, as Cahill’s four-seamer never garnered high whiff rates. He’s also used the cutter in place of a sinker at times against left-handers. He’s been a bit more hesitant against lefties with the pitch, throwing it mainly when he’s ahead in the count. Against right-handers, he’s actually been using it as his secondary strikeout pitch.

During his first season throwing the cutter, it emerged as arguably his third best offering. Cahill was able to pound the zone more effectively with his sinker, but the cut-fastball was able to get whiffs. While the sinker was pounded into the ground at a higher rate, Cahill’s 55.88% GB/BIP rate on the cutter was also impressive. The slider may have been Cahill’s most reliable pitch, but its ability to get whiffs continues to be a glaring weakness. Cahill’s cutter emerged as an all-around decent offering, that had a slightly higher upside due to its whiff rate. Early on, he’s shown an increased mastery of the pitch. It’s foolish to completely dig into the results after just three starts, but most of his trends with the cutter are moving in the right direction. He’ll have to retain those over a much larger sample in order for them to become significant.

The introduction of a cutter helped Cahill grow as a pitcher last season. Realizing that, he’s started relying on the cutter a lot more this year. Based on how well the pitch helped him last season, this seems like the right strategy. At the very least, the improvement Cahill showed last season should be retainable this year. If he’s able to improve on the pitch during his second season using it, or the change in approach works out, there’s still a chance for another small improvement from Cahill.