Update: He's just signed with Oakland.
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Ben Sheets is a sexy name who's been popping up recently in connection with the Mariners. Make no doubt about it, when Sheets is healthy, he can be every bit as productive as a Felix Hernandez or a Cliff Lee, but that's just the problem - he's never healthy. On paper, Sheets is more than capable of putting together a five win season, but if you gamble on a guy's maximum upside, you're a fool. There's a tremendous risk that a team signing Ben Sheets for a year will see absolutely nothing come of their investment except a gargantuan medical bill.
Sheets says he's healthy, and apparently teams were impressed by a recent workout. He's also asking for significant money (in the eight to ten million dollar range) in order to acquire his services. Now, despite Jack Zduriencik's plea to stop speculating about the Mariner payroll, I'm fairly confident that we could afford Sheets at most any price he'd care to name. But that's not the right question to ask - what we really want to know is what would he be worth to the Mariners.
How do you feel about our rotation? After Felix and Lee, there's a big drop to Ryan Rowland-Smith, and after our favourite Australian comes Ian Snell and any one of Jason Vargas, Garret Olson, Luke French, Doug Fister... you get the drift. We are absolutely awash in fifth starters, but the reason they're all having to compete for a job is that they're not very good. Replacing that last spot with Ben Sheets is a clear upgrade, and we certainly have the depth to cover him if he goes down with an injury.
I think a reasonable estimate for a healthy Sheets is a 4.5 WAR season. He's not quite in the top class of pitchers, but he's not far behind. In fact, he's a lot like another pitcher who was strongly linked to the Mariners: Rich Harden. Granted, Sheets is a fastball/curve guy and Harden relies more heavily on his changeup, but they match up perfectly as oft-injured aces. Harden's contract with the Rangers sheds a little light on how the Mariners value the injured-fireballer package - i.e. less than $7.5M with escalator clauses. How much less, we don't know, but that's probably the upper bound.
But should Sheets be valued exactly the same way Harden was? After all, Rich Harden's managed a couple of almost-full seasons lately, and Sheets sat all of 2009 out with elbow problems. Let's compare how many starts the two have missed since 2004 (assuming 34 starts per full season):
Figure 1: Harden vs. Sheets - Missed Starts since 2004 (and Projected 2010)
I've also added projected starts missed in 2010, using an 5/4/3 rating for '09/'08/'07 respectively, giving Sheets 16 starts and Harden 20. Feel free to argue with the way the past few years are weighted, as I just used the Marcel weights in lieu of putting any real thought into it and injury prediction is a hilariously inexact science. Call those numbers x_s and x_h, if you like. Anyway, if you assume that Sheets and Harden have equal ability (this seems entirely reasonable), Sheet's worth to the Mariners is roughly $7.5M*x_s/x_h, which by my reckoning is $5.25M plus escalator clauses. Of course this all depends on one's assessment of his health. You could quite quickly drop below four million if you penalise him more harshly than I for missing all of last year, but I don't see much of an argument for going higher - I think that my quick estimate above is a decent measure of the upper bound for what he should be earning in 2010.
PS: I want to extend a personal thank you to Mr. Sheets for not signing a contract today and therefore letting me have something to write about. Cheers.