There was a time when Aaron Cook averaged almost 200 innings a year. From 2006 through 2008, Cook crossed the 200 inning threshold twice, averaging 197 per year over the stretch. Throw 2009 in, and it's still 187 innings per year over four seasons. He was productive, too, posting a 116 ERA+ despite under four strikeouts per nine, thanks to his extreme groundball tendencies.
He hit the disabled list a few times during those four years: an oblique strain in 2007 cost him 48 games, while a 2009 right shoulder strain landed him on the DL for 31 contests. Generally, though, Cook was healthy and more than competent, despite the tough environment of Coors Field.
Things have gone completely downhill for him since, as Alex Speier discussed last week:
"This is the first offseason that I've had in about two or three years where I was completely healthy and I was able to do all the work I needed to do," said Cook.
Two offseasons ago, in an effort to counter a turf toe issue that hampered him in the 2009 season, he felt that he dropped too much weight (down to what Rockies observers at the time thought was a rail-thin 200 pounds). In 2010, his season was ended by a Joey Votto line drive that broke his leg and the recovery process left him unable to build up his legs for 2011. He also dealt with shoulder inflammation that restricted his ability to build arm strength in the offseason. Then, early in spring training, he broke his finger, an injury that impacted his feel for the ball all season.
Cook's downward injury spiral might have reached its end, since for once he didn't spend the winter recovering from one malady or another. Then again, spring training hasn't happened yet, so there's still time for yet another appendage to give out before the real season begins.
Cook has mostly had weird injuries throughout his career. While his throwing shoulder has had a few issues (including thoracic outlet syndrome eight years ago) it's never been a re-aggravation of an injury -- just the usual wear-and-tear that occurs to a pitcher who has over 1,300 innings in the majors under his belt. The thing is, he always seems to get these weird injuries -- turf toe, broken fingers, fallout from being hit by liners -- and they always cost him significant time.
Is he frail or unlucky? Maybe it's a bit of both, as quoted above. Baseball Prospectus's injury projection system, affectionately nicknamed "CHIPPER," forecasted Cook as being pretty likely to miss at least 30 days last season based on his history, and that was before the spring training finger fracture that ended up messing with his year.
Healthy Cook has produced above-average results. Unhealthy Cook has struggled a bit more, but it's been almost entirely due to an increase in walks. His groundball rates (and ground-to-fly ratios) have been very consistent, whether he's feeling good or not, and his strikeout rates have actually risen over the years. If being healthy and feeling good helps him keep consistent and strong throughout the year, maybe we see his walk rates drop back to where they used to be, resulting in the above-average Cook of old. He has a contact-heavy approach, but with Dustin Pedroia, Adrian Gonzalez, and possibly a good bit of Nick Punto in the field, that won't be an issue -- last year's Red Sox ranked 11th in the majors in turning groundballs into outs, and should be able to play Cook's game again this year.
If that were to happen, the Red Sox would actually have a pretty good starter on their hands already, and for the grand total of $1.5 million. If Cook is healthy, he'll likely be on the major league roster, and any issues surrounding his multiple opt-out dates might never even come up -- it's not like he's going to choose to leave if things aren't going well for him, so this could be pretty win-win for the Red Sox.
Of course, there's no guarantee Cook is going to be healthy. It's been one thing or another for years now, and he's averaged just 162 innings a year since 2006 (and 144 innings per year since he became a full-time starter in 2004). But for the cost, given the upside, Cook could turn out to be a much better signing than many -- including me -- gave it credit for when it happened.
It's a roll of the dice, but considering the Red Sox can attempt to make a trade later (and employ the likes of Vicente Padilla and Alfredo Aceves), seeing if Cook can make it through spring training with all of his fingers and toes attached isn't a bad plan. It's one that hasn't worked out for the Rockies the last few seasons, but unlike Colorado, Boston isn't throwing $10 million down per year to bet on his health. Given Cook turned down guaranteed deals to pitch with Boston, you have to think he's betting more heavily than the Sox this time around.