[Stats exclude all relief appearances]
This is a borderline equals, Cahill's ERA increasing by 0.21 runs, with FIP up about double that. However, this was largely due to one really bad June: he had a 9.85 ERA and the only one of the six starts he didn't lose was limited by a comebacker to one inning. Over the rest of the season, his ERA was 2.80 in 19 starts (and one emergency relief performance), with a mechanical tweak apparently helping significantly after his return from the DL. Cahill adjusted his arm-slot, raising his delivery - you can see the difference in this picture, comparing Cahill pitching to St. Buster on June 8 and August 31. That helped re-establish his sinker, and generate more ground balls.
A remarkable blossoming by Corbin, who came in to spring training as merely one of three candidates for the fifth starting spot. He won that, pitched like a legitimate Cy Young candidate in the first half, absolutely deserving his All-Star selection, and even though he seemed to run out of gas in the second half of the year, still had the best ERA of any Diamondbacks' starting pitcher. I was concerned by his last seven starts, over which time opponents hit Corbin at a .346 clip, and he had an ERA of 8.00, even though his innings total wasn't excessively up over 2012. Hopefully that was simply the increased effort of the majors, and he'll be better equipped to go all the way next year.
After a disappointing spring training, Delgado went to Reno, but was brought into the rotation as a hold-over while Ian Kennedy was suspended in late June. The loss of Cahill to the DL extended his stay, and with the exception of one glaring issue, Delgado pitched well, holding opposing hitters to an on-base percentage below .300. The problem, of course, was the long-ball, with an overall rate of 1.86 per nine innings, among the highest in all baseball. It seems to be a locational issue, and when he misses his spots, hitters are able to take advantage. However, worth remembering he's only 23: at that age, Miley, for example, was mostly in high-A ball.
Holmberg's arrival was highly-anticipated, rated by John Sickels as the #5 prospect in our system before the season began. He got his chance on August 27, being promoted from Double-A Mobile to make a spot start in place of Cahill, after the latter had to work multiple innings out of the bullpen, but it wasn't a debut to remember. While the Diamondbacks won, Holmberg was charged with three runs on six hits and three walks in just 3.2 innings, without recording a strikeout. He'll still get his chance, but this season wasn't it.
Our Opening Day starter got the win there, holding the St. Louis line-up to two runs over seven innings. However, his remaining 20 appearances as a Diamondbacks would yield only two more victories, and by Game Score that first performance was also his best for Arizona. The rest included a reprise against the Cardinals, who smacked Kennedy around for 10 ER - one of only five D-backs starters ever to allow that many in a game. At the trade deadline, our #1's stock had dropped so low, he was traded to the Padres for a left-handed reliever and a relief prospect, a sad end for a man who went 21-4 for us just two years ago.
Given he had averaged 14.5 games per season from 2007-12, McCarthy making 22 starts wasn't too bad: he was signed almost with the expectation that there would be time on the DL. However, Brandon struggled out of the gate, opposing batters clobbering him at a .351 average through his first six starts - some of that was bad luck, with a .393 BABIP, but a 26% line-drive rate shows a lot of too-good contact. Like Cahill, McCarthy tweaked his mechanics in August, and the results thereafter were better, with a sub-three ERA over his final seven outings. However, the 5.44 ERA he posted to that point made it too little, too late.
No-one realistically expected Miley to reproduce his near-Rookie of the Year season in 2012, but he made a more than respectable attempt: his ERA was up barely two-tenths of a run, and his xFIP was virtually unchanged. There was some regression to the mean in his home-run rate, which increased from 0.65 per nine IP to 0.93, and his control, a key factor in last year's success, dropped from awesome to good. Miley struggled early, with an ERA above five through the first two months, but he seemed to get the walks back under control at the end of the year, and ten more scoreless innings would have let him pip Corbin for the team ERA crown.
Skaggs' debut season last year was underwhelming, with an ERA of 5.83 in six starts, but much better was expected this year, even though he was only 21 when called up for the first time, as part of the double-header on May 27. That went well, Skaggs three-hitting the Rangers over six shutout innings, but his next two outing both led to five earned runs, and was sent back to AAA. Skaggs accumulated further mileage, over two subsequent call-ups, but the results were inconsistent. He had eight brilliant innings against the Rockies, then allowed 12 ER in 14 IP over his next three starts. That marked the end of his season, but again: he's still only 22.
Spruill was one of the pieces received from the Braves in the Upton trade, and made his major-league debut out of the bullpen in June. At the start of August, he was called up again, and made a pair of starts. Neither went well, as he failed to record an out past the fourth innings, though wasn't helped by the four unearned runs his defense allowed in Zeke's second game. However, the three home-runs allowed to the Rangers in his first start as a Diamondback? Those were all his.