In the world of baseball, there are smart signings (Cody Ross, Adrian Beltre), there are stupid signings (Carl Crawford, John Lackey), and then there are obvious signings.
David Ross is an obvious signing.
It's an unusual situation that leads to a backup player earning that designation, but if ever there was a situation where that was more about the man with the starting job (one Brian McCann) than the quality of the backup, this is it. However good David Ross was, before this unfortunate season McCann had hit .286/.358/.486 as one of the top defensive catchers in the game. Simply put, he's a star.
David Ross, however, has been no slouch himself. Though a late bloomer, Ross has produced at a very impressive level for a catcher over the last seven years, hitting .245/.336/.457. That line is even better over just the last four with Atlanta: .269/.353/.463 in a park that, as Marc mentioned, is not great for right-handed hitters. This coming, of course, in the years immediately after Boston let him walk following a short stint on a minor league contract.
Perhaps even more important than his solid bat, however, is Ross' glove. Consistently ranked as one of the best defensive catchers by those who try to quantify that sort of thing, Ross manages to save as many runs as most good defensive catchers despite often seeing half as many pitches. What's more, often enough those rankings don't even include the ability of a catcher to frame pitches, turning balls into strikes. Possibly the single most important aspects of a catcher's job, framing also happens to be Ross' specialty. Depending on who you ask, Ross is either a very good framer, or one of the absolute best in the game. It's a skill that the Red Sox could really use for a guy like Jon Lester, who seemed to fall apart when he didn't get calls last year.
Unfortunately, it's too late for David Ross to start playing 140 games a year. At 36 that's just not a transition that can be made. But as a backup--or "something more" as Ken Rosenthal says the Red Sox are thinking--there's few guys more flexible. He should make the pitchers happy given his reputation behind the dish (and in the clubhouse), and given his pretty much even splits, can pair with any catcher the Red Sox have or choose to acquire down the line.
Of course, it's possible that Ross, at 36, has reached his limit. It's possible that the Sox just committed themselves to two years with a guy who's going to start declining and never look back. If that's the case, then they're out all of $3.1 million for each of the next two years (again, per Rosenthal). Since Ross is a backup, it's not like the Red Sox have shut themselves out of any catching market they'd otherwise be active in, and with so few options out there, it makes all the sense in the world given the minimal financial risk involved.
It's the first real move of the offseason (re-signing Ortiz has been a given since the Sox got rid of all that money), and by all appearances, it's a no-brainer. Well done, Mr. Cherington.