I got the Kindle version of The Hardball Times annual for my birthday and the first thing I wanted to read was the article about Tommy John surgery. It looked at whether pitchers get back to the level they were at pre-surgery and when that is. They also looked at what the shelf life is for a pitcher who had the procedure before he needs another visit with the surgeon. It's a really good article and if the rest are anywhere near as good as that one, I'll be very pleased with the book.
I was thinking about what this meant for Scott Baker as I was reading it. For one thing, we should not expect Baker to be at his pre-surgery production level, but I doubt anyone was expecting that anyway. The first year back is more difficult and their performance just isn't as good. It's good to know that by year two the performance level is back to its pre-surgery level. There was also a velocity drop in the first year back, but it returned in the second year.
The authors, Brian Cartwright and Jeff Zimmerman, looked at percentage change in ERA, HR/9, BB/9 and K/9. I'd have preferred they look at percentages rather than rates, but that's what I have to work with.
I used the playing time adjusted CAIRO to create a new TJS adjusted projection for Baker.
Original CAIRO: 120 IP, 13 HR, 38 BB, 100 K, 4.49 RA, 4.19 ERA, 3.82 FIP
TJS-adjusted: 120 IP, 14 HR, 42 BB (BB-IBB+HBP), 4.82 RA, 4.43 ERA, 4.19 FIP
They also found that among the pitchers who were successful in their return, a second surgery was likely down the road.
Here’s a good rule of thumb: If a post-surgery pitcher is able to reach 100 innings pitched in a season as a starter or 40 innings pitched as a reliever, it is reasonable to say that he won’t need an immediate repeat of the surgery. However, if the pitcher is able to make it back pitching regularly, he then falls into the group of pitchers who begin to wear out their elbows again and need a second TJS.
The time frame for a second surgery, after pitching at full capacity, starts at approximately 400 innings. Here is a list of pitchers who pitched after one Tommy John surgery and were able to return to the majors yet eventually needed a second time under the knife.
Baker is a free agent after the 2014 season so this isn't going to be an issue for the Cubs, but they will get only one season in which he's back to full form, or rather they can only expect to get one season. Depending on how much he pitches in 2013 and 2014, it might be in the Cubs interest to let him walk when his contract is up.
Andrew corrected me in the comments regarding Baker's eligibility for free agency. He is a free agent after this year.
Interestingly, Kerry Wood lasted the longest among the pitchers they looked at in the book. He threw 876 innings before needing a second surgery.
I'm not sure if I'll be doing the aggregate projections this year. I'm inclined not to do it because Fangraphs has most of the available projections available on the player pages. It's something I've enjoyed doing the last several years, but that was in part because it was a lot of fun to look at the Cubs projections back in 2007, 2008 and 2009. Since then it's become more of a drag and thruthfully, I couldn't give two shits what the aggregate projection for James Russell is. Nor could I care what it is for Scott Feldman and the other 11 starting pitchers the Cubs have.
It's something I may yet do. Most of the projections aren't out yet so who knows, but if I don't do it, I'll be using the CAIRO projections unless otherwise noted.