Paul Maholm and Jason Jaramillo don't mix
I noticed something interesting with Paul Maholm recently. Maholm started the season off with a bang, allowing just two runs in 20.2 innings pitched. Then he started to struggle, with 18 runs allowed in his next 23.2 innings pitched. That was until his last two starts, where he threw 13 combined innings, with just one run allowed.
So what happened during that four game stretch? Could it be Jason Jaramillo?
Maholm was caught by Ryan Doumit in his first three games. With Doumit out, Jaramillo took over as Maholm’s catcher for that horrible four game stretch. Diaz took over in the last two starts, and Maholm rebounded back to his success from the first three games.
Maybe this is just a coincidence. Or maybe not.
Looking at the other Pirates’ starters, we get the following splits:
The only pitchers having success with Jaramillo are Ross Ohlendorf and Zach Duke, of course Duke is having success regardless of the catcher, while Ohlendorf doesn’t have the best ERAs with Doumit and Diaz.
Then there’s Jeff Karstens. Karstens had his first four starts with Jaramillo, allowing 13 runs in 20 innings. His next two starts were with Diaz, where he went six innings each time, allowing two runs in the first start, and three runs in the second start. His most recent start was with Jaramillo, with four runs allowed in six innings.
Finally we have Ian Snell. Snell struggled in his first start with Doumit, but rebounded nicely with two runs allowed in 13 innings over his next two starts. Since Doumit has gone down, Snell has six starts. His two starts with Diaz were both quality starts, with four runs allowed in 13 innings. His four starts with Jaramillo yielded 14 runs in 18 innings, with his only quality start coming tonight.
Overall Doumit and Diaz have spectacular ERAs in their time with the starters. Jaramillo on the other hand has a 5.19 ERA in 95.1 innings with the rotation. This is mostly due to Maholm, Snell, and Karstens, who all have had success with Diaz, with Maholm and Snell having success with Doumit as well.
Based on this information, and the hitting differences between the two catchers (Diaz at .306, Jaramillo at .255), I’d give Diaz the bulk of the starts until Doumit returned (starting Jaramillo only with Duke and Ohlendorf), and when Doumit returns I’d keep Diaz in the majors as the backup.