FanGraphs from October 29, 2009:
The Red Sox may employ the smartest front office in baseball, which is why this tweet from Jon Heyman makes little sense. Heyman suggests the Red Sox are willing (and able) to offer Jason Bay a four-year deal worth approximately $15M per season.
Bay turned 31 about three weeks ago and is fresh from his best season in years. Since moving to the American League in July 2008, Bay has seen his strikeout rate leap in upwards to 30%. Bay strikes out, walks, and hits home runs. Two of those qualities are great to have and make the third tolerable. The problem begins with his age. He’s on the wrong side of 30 and while he does play in a notoriously hitter-friendly ballpark, his bat is likely to decline over the next four years instead of remain static or (somehow) improve.
This would be fine if Bay’s value was supplemented by playing a key defensive position or at least playing defense moderately well. Instead, Bay is anything but a black hole in left. Bay has posted negative UZR in each season since 2004 with the exception of 2006. His arm has never been good, and whatever range he has left isn’t enough to make up for it.
Then the same site on November 9, 2009:
If you want a right-handed hitting outfielder this winter, and you don’t want to pony up for Matt Holliday, Jason Bay is not the alternative. Call Mike Cameron instead.
From a November 19th Baseball Prospectus Joe Sheehan chat:
Phil S. (NJ): Bigger free agent "fool's gold" – Bay or Lackey?
Joe Sheehan: Bay.
And Eric Seidman, also from a BP chat earlier today:
Eric Seidman: The latter. If they are going to "overpay" it should be in terms of talent to acquire the likes of Cabrera or A-Gonz, not with Bay. The Red Sox had the 3rd worst PADE this year and Beltre/Cameron would really improve that facet of their game.
So maybe it would be better to stay away from Bay?