Casey Kelly Debuts, Questions Remain

One of the main products of the last big Adrian Gonzalez trade debuted for the Padres last night. Though he didn’t allow a run to the Braves in six innings, Casey Kelly’s first start was — much like the rest of his professional career to date — uneven with a chance of sunshine.

Going into the season, our own Marc Hulet ranked Kelly the sixth-best prospect in the Padres organization, and he wasn’t alone in his lukewarm appraisal. He gave Kelly about the same upside as the seventh-ranked prospect (and second-highest-ranked pitcher) Robbie Erlin, but opinions were divided about the two prospects. John Sickels had Kelly eighth (B/B+), Kevin Goldstein had him seventh (five behind Erlin, with four stars) and Baseball America had him fourth (five ahead of Erlin). Most had reserved praise for Kelly, along the lines of Hulet’s succinct appraisal:

Kelly, though, did not strike out many batters and never really has and he also gave up a lot of hits – both of which combine to limit his ceiling a bit. His heater does get good sink and he induces a lot of ground-ball outs so he’ll need a strong defense behind him. Kelly’s repertoire includes an 88-94 mph fastball, potentially-plus curveball and a developing changeup.

The Padres right-hander did show all of those pitches in his first career start, and that alone has to be seen as a small victory. If the changeup had not developed into a useable pitch, it’s not likely Kelly would have used it against major league hitters. That said, he didn’t throw a ton of them — six on the night, out of 87 — and he only got one whiff on the pitch. Averaging 84 mph, the pitch didn’t quite have the benchmark 10 mph difference off his 92 mph fastball, but it was obviously effective enough. The pitch broke 6.85 inches horizontally and 4.06 inches vertically according to Brooks Baseball, and both of those numbers are middle of the pack. The changeup most like his is probably Mark Buehrle’s, which is strange since he’s a lefty, but he’ll take it.

As Hulet’s thumbnail suggests, Kelly’s fastball velocity has been up and down over his career so far. On Monday night, it was more of the same, as he lost a little gas as the game went on:

After touching 95 a couple times in his first ten pitches, Kelly maintained velocity around his 92-mph average until somewhere around his 70th pitch. Then it was a slow decline into the high eighties. This might be related to his current season — he’s had inflammation in his elbow that has limited him to fewer than 40 innings so far in 2012. Seen in that light, the velocity decline is not a big deal, but it might also point to the fact that the Padres are not likely to allow him to pitch too deep into games. That might make wins difficult for Kelly.

The curveball, his best breaking pitch, did get him three whiffs (on 20 pitches). With 6.35 inches of horizontal break and 4.45 inches of vertical break, his curve is a little like the one Ubaldo Jimenez uses (5.6, -4.4). Linear weights don’t love Ubaldo’s curve, and he has been using it less (with less movement) recently, but over his career, the curve has led to a 43 wRC+, the lowest on his ledger. Ubaldo gets a sub-par swinging strike rate on the pitch though, and Kelly’s three whiffs on 20 pitches would almost double Jimenez’s swinging strike rate if he kept up the work all year. It’s a good pitch.

Overall, Kelly got six ground balls against five fly balls. Since fifteen batters made contact, that means his ground-ball rate (40%) left something to be desired. We’ve only got one game of data, so it’s worth wondering if this strike zone plot says he was showing his usual strong control by staying near the corners and in the strike zone, or if it shows that he could keep the ball down a little more even:

After one start in the bigs, we know about as much as we knew before: Casey Kelly has a good curveball, inconsistent velocity, and a useable changeup. Along with his home park, that probably makes him a spot starter for now, but obviously keeper league owners and Padres fans will be watching his next start just as closely as the first. More information will help us clear up Kelly’s place in Major League Baseball (and the fantasy game, as well).