Sergio Romo Out — Who’s In?

Sergio Romo is out. The committee is in. And so we get our divining rods out and try to figure out who will leave the heap on top.

I’ve talked about Jack Moore’s great piece on the relevance of strikeout rate and velocity on possible closer changes before, so it seems relevant to mention now that only Koji Uehara has a slower fastball than Romo among relievers with more than two saves. But it’s working for Uehara, based on awesome command (3.2% career BB%) and a great splitter. Seems like Romo’s awesome command (5.2% career BB%) and great slider should be enough, particularly since he added a change-up this year.

But Romo, he hit a bad stretch, and now velocity and strikeout rate are relevant. Let’s just make a handy chart then.

Santiago Casilla jumps off the page when it comes to velocity, even if he cedes some strikeout ability to other pitchers on the list. By this analysis, his biggest competition comes from Juan Gutierrez and Jean Machi. Let’s call it close enough to try and parse the difference — all three are obvious being used in close and late situations, given their holds numbers.

Of course, we’ll have to go off the reservation a little to do this. There’s very little correlated with closer change in a meaningful way when you ask the numbers. So let’s freelance for a second.

Juan Gutierrez has been a find this year, using improved command — or a nice home park — to avoid homers at a career-best rate. The culprit in the past has been his change-up. He has the highest homer rate on his change-up among any of his pitches. Despite it having a great whiff rate (22%), it’s risky pitch. He doesn’t throw it a lot, though. More important is perhaps the fact that BrooksBaseball has him throwing a worse slider more often than his better curve ball. But he can command the curve. In any case, Gutierrez is being used in losses — five straight in fact. Usage suggests he’s not a contender.

Jean Machi has 93 mph velocity, a better strikeout rate, and was used in a win more recently. If his last two bad outings can be ignored, he might be a better option than Casilla. He was once a closer in Mexico! (Yes, that’s irrelevant.) Machi is very Uehara-ian in that he throws the splitter almost as much (if not more) than his fastballs, and it’s working because so far he’s shown excellent control. The only thing that’s weird about Machi’s line is that his major league walk rates have all been far superior to his minor league ones. Only once did he have a walk rate under 6% in the minors, and his major league walk rate is 5.5%.

Casilla has the best velocity of the three, but the worst strikeout rate. It’s the worst strikeout rate of his career, and really only his fastballs and curve are any good by whiff rates, so it’s not surprising. His sinker gets 73% grounders, though, so he’s a fairly safe pitcher. It’s strange that his fastball usage is down recently, but we haven’t heard that his recent hamstring injury is acting up or anything. Casilla has also been used in wins and gotten more holds than the other three recently.

Jeremy Affeldt is reportedly part of the picture, and has been used in close and tight games. He’s also no LOOGY — Lefty One Out GuY — not with a 3.87 vs 4.03 L/R FIP platoon split and a curve/splitter platoon-busting arsenal. But a recent breakdown doesn’t bode well, and managers don’t prefer lefty closers. His velocity is the worst of the contenders, and his strikeout rate does not seem to do enough to make the case by itself.

Given that the Giants are in contention, it seems doubtful they’ll hand the role to a newbie, even if closer experience hasn’t been shown to be predictive in the past. So even if Jean Machi could close for the Giants in the long-term future, the near-term future seems to be all Santiago Casilla’s.

At least until Sergio Romo gets it back. After all, Casilla was once the closer before Sergio Romo, so they’ve proven the hierarchy once before. And look through Romo’s peripherals, and it’s virtually impossible to find anything that’s out of whack with his career numbers. Sure, he’s throwing the change more, but none of the homers that are mucking up his overall line have come off the pitch. Expect a little homer regression and Romo to get his role back from Casilla in the future.