I've always suspected that Spud Chandler was juicing. And Jamie Moyer. And Jim Perry. And Warren Spahn (especially Warren Spahn). And Bert Blyleven. And Preacher Roe. And Lefty Grove. And Steve Carlton. And maybe Roger Clemens, Kevin Brown, Randy Johnson, John Smoltz, David Cone and Nolan Ryan. And certainly Gaylord Perry--heck, you could see the tobacco juice stains he left on the ball!
Those are all pitchers who had very good seasons at age 38. There are more: I think that I've made my point.
But Mike Mussina is going to be 39--let's look at age 39, and let's be a little more critical--let's look for comeback seasons from an ERA+ around or under 100.
Early Wynn went from 14-16 at age 38 to 22-10 at age 39, dropping his ERA by almost a run...Rick Reuschel's bad year was at age 37, not age 38, but he came back from a 9-16 record to a 19-11 record at age 39...David Wells went from 5-7 at age 38 to 19-7 at age 39...Kenny Rogers went from 13-8 to 18-9 at age 39...Sal Maglie went from 9-7 to 13-5, with an ERA+ of 140 and 191 IP at age 39...Fergie Jenkins went from 5-8 to 14-15, with an ERA+ of 118 and 217 IP, for the hapless 1982 Cubs, at age 39...Don Sutton went from 8-13 to 14-12 at age 39...and let's not forget that Connie Marrero improved in ERA+ at ages 39, 40 and 41, probably hitting his peak at age 40.
Gaylord Perry, of course, won a Cy Young at age 39, but he pitched well at age 38, too, and we all now know that he juiced.
Curt Schilling went from 8-8 to 15-7 at age 39.
Mussina's 90th percentile PECOTA is a 3.60 ERA in 174 IP. That would probably put him in the top 20 pitchers in the AL. There's roughly a 10% chance that Mussina would do even better, if you follow PECOTA. When one does better than being in the top 20, it's not a far reach to one's being a Cy Young candidate...particularly in New York, particularly with the Yankees batting order scoring your runs for you.
I expect Mussina to pitch more innings. Right now I think that it's nip-and-tuck which one will end up with a better ERA--but keep in mind that Colon was a throwaway for a reason, and that he's far too heavy for his role.
But your challenge regarded my estimation of upside for Mussina. I've given you several cases of pitchers who CAME BACK at age 39. There are more who simply did well: these are all pitchers who had been mediocre to bad, but who had regained their greatness. My list isn't inclusive: there are probably more.
I'm shocked that you would even suggest such a thing.
No, I'm serious: Mike Mussina's UPSIDE is Cy Young-contending caliber. It's just that I don't see Mussina approaching his upside...hope that I'm right on that account.