The Subtle Improvement of Trevor Cahill

Trevor Cahill has mostly been a disappointment in fantasy leagues. Much of that has to do with lofty expectations from his owners following a lofty 2009 prospect ranking. Cahill happened to win a spot in the Oakland Athletics’ rotation that season, but wound up disappointing, failing to carry his above-average strikeout numbers in the minors to Oakland. An inability to record strikeouts has been Cahill’s major flaw over his four big league seasons. Last season, Cahill made some strides in that area, posting the highest strikeout rate of his career, which contributed to his strongest season to date. While Cahill is far from a fantasy ace, the improvement could make him a solid mid-to-late round pick this season.

One of the biggest reasons for Cahill’s career-high strikeout rate last season, seems to be the development of a cutter. The pitch has been mistaken for a slider on some pitch tracking systems, but it comes in at about 85 mph, two ticks faster than Cahill’s slider. Cahill wasn’t shy using the pitch, especially against right-handed hitters. Outside of his sinker, the cutter was Cahill’s second most used pitch against righties. In two strike situations, Cahill used the pitch 20% of the time. It seemed to keep righties off balance, too. His strikeout rate against right-handers jumped to 20.2% last year, a career-high. While the pitch is still labeled a slider according to PITCH f/x, it rated as Cahill’s best pitch last season using pitch type values.

The addition of a cutter helped Cahill’s other secondary offerings as well. Because Cahill now had another weapon to neutralize righties, hitters couldn’t sit sinker of change-up anymore. His usage with the pitch against right-handers dropped from 17% to 13% last season because of the cutter. Whether it’s due to his cutter, or just plain improvement, Cahill had much more success with his change-up last year. In 2011, batters hit .295 against Cahill’s change with a .455 slugging percentage. Those numbers plummeted to a .191 average and a .355 slugging percentage in 2012.

Cahill’s usage of those pitches has come at the expense of his curveball. While Cahill’s curveball was often thought to be his big strikeout pitch, it rated as his worst pitch according to pitch type value during his first three seasons in the league. His usage decreased from 13.6% in 2010 and 2011, to just 7.1% in 2012. It actually may have helped, as Cahill finally had a positive type value with his curve last year.

Cahill is not an elite command guy, so he needs to have a decent strikeout percentage in order to be an effective fantasy pitcher. With his increased rate last season, he definitely had value. And since his FIP matched up with his solid ERA, there’s reason to believe he can do it again. At age-25, there’s still some hope for a little more improvement, actually. In late September, Mike Podhorzer outlined pitchers who were due for a strikeout surge. He concluded that, based on Cahill’s SwStk%, he should have been striking out more batters. People seem to be focused more on what Cahill couldn’t do his first couple of years in the majors. But he’s slowly increased his strikeout rate to an acceptable level, and there’s evidence that a new approach played a big role in that improvement. He’s far from an ace, but he may have become an undervalued asset in fantasy leagues.