Trevor Cahill’s Recent Success: In Depth Look


Aug 15, 2014; Miami, FL, USA; Arizona Diamondbacks starting pitcher Trevor Cahill (35) throws against the Miami Marlins during the fourth inning at Marlins Ballpark. The Arizona Diamondbacks won 3-2. Mandatory Credit: Steve Mitchell-USA TODAY Sports

There is no doubt that Diamondbacks starting pitcher Trevor Cahill has been inconsistent all year long. The inconsistency of the whole entire starting rotation, along with a devastating injury has turned something that was predicted by many to be a strength of this team coming into this season, into a disappointing part of this lost season. As a whole, the Dbacks rotation has the fifth worst era in baseball at 4.30, and they only have 57 quality starts at staff, which is the fourth worst in baseball.

Cahill was struggling in the early part of the year ,and was demoted to the bullpen on April 14th after just four starts. In his first three starts vs. the Giants, at the Giants, an, vs. the Dodgers he allowed fourteen runs, thirteen of those earned runs, and his FIP was 5.62. I prefer FIP or Fielding Independent Pitching over ERA or Earned Run Average because it’s a better way of measuring a pitchers value. FIP just measures K/9, BB/9, HR, and HBP during a given outing. It doesn’t take into account things that are out of a pitchers control such as an infielders or outfielders range. It basically takes balls in play or BABIP out of the equation while era doesn’t. FIP is a better metric of gauging how well the pitcher does by himself.  Clearly something was off with his mechanics and his control during his first three starts.

I did some research on the first three months from April to June before he was sent down to the minors to work on his mechanics and his release point, and then I looked at the month of July, and his first three  starts of this month not including tonight’s start.

When Cahill pitching effectively, he is using his sinker at a high rate and getting a high percentage of groundball outs. The other key for Cahill is having pinpoint control and not walk a ton of people. Let me clarify for those that don’t know: there is a distinct difference between command and control even though some have differing opinions. Control is the ability to throw all of your pitches for strikes, and command is the ability to locate all of your pitches in any part of the zone.

First I examined his ground ball percentage, and how often he was throwing his sinker. Now we already talked about his first three starts before he moved by the pen. Since I am examining April-June first, keep in mind that his stats are based on some time in the rotation, and some time in the bullpen, so BABIP has to affect those numbers, and while he is in the pen, he was striking out more batters because that is what usually happens.

From April-June, Cahill started three games, and the rest of his appearances we’re out of the pen. In his first three starts according to FanGraphs, his GB% was 50% and he was using his sinker 57.9% of the time which is slightly below his average for the entire season to this point.

After the All Star Break, Cahill moved back to the starting rotation. So all of the numbers from July, and his first three starts in August. From July 18th to August 15th, Cahill’s GB% was 51.4 which isn’t a huge jump, but it’s higher. He also was using his sinker a little more often at 59.8% of the time. The way he pitches, a little difference can make a huge difference.

I then looked at K% and BB%, and his FIP. I prefer K% and BB% over K/9 and BB/9 because the percentages are easier to calculate, and it takes into account that some pitchers face more batters than other pitchers in a given inning. From April to June, his K% was 25.6 and his BB% was 12.5. Based on FanGraphs measures, he was at the two extremes. His K% would be considered excellent, and his BB% was considered awful. No wonder he wasn’t feeling confident on the mound, and his FIP was 3.91.

Other factors such as mechanical issues, confidence, and release point issues factor in, but the numbers are saying something. From July-August, his K% was down at 17.6% which is normal. The big part is his BB% which dropped all the way down to 5.4% which is considered great. As a result, his FIP goes down to 2.88, and he is actually winning games for his team which means he has more value. Their is a clear tie with BB%, FIP, GB%, and SI% all keys for Cahill.

Of course, the Diamondbacks want to shred some payroll, and Cahill is owed a lot of money. He is owed $7.7 million this year, and 12 million next year. So the Dbacks need him to perform well, so he can be valuable in a trade in the offseason or next trade deadline, because there is no doubt that he won’t be on this team at some point in the near future.

Aside from all the statistics, Cahill is feeling more confident on the mound since he came back from the minors. This is what Cahill told Arizona Republic beat writer Nick Piecoro:

“Anytime I feel like I can throw the ball somewhat where I want to, I feel a lot more confident,” he said. “It’s tough when you’re throwing and your stuff is kind of going all over the place. You start competing against yourself more so than the other team. Just the fact that I feel like I can locate two or three of my pitches definitely helps a lot.”

The bottom line is that the numbers and his confident point to a clear trend that I believe will continue.