Looking at his overall numbers in 2012, it may seem like a worthy signing for the beleaguered squad.
But it isn't.
Dempster posted a 3.38 ERA, 1.20 WHIP and 153 strikeouts in 28 starts (173 innings) in 2012. Given that the Red Sox registered a starters' ERA of 5.19 last season (12th in the AL), it looks like an obvious win for Boston on the surface.
But, look below the surface and you uncover something ugly.
First of all, Dempster had pitched in the National League for his entire career before being traded from the Chicago Cubs to the Texas Rangers last August. And the jump to the American League did not work out well for the 35-year-old.
Dempster had a 2.25 ERA and 1.04 WHIP in 16 starts for the Cubs before the trade deadline.
With the Rangers, however, he posted a 5.09 ERA and 1.43 WHIP in 12 starts. Not exactly earth-shattering numbers.
Was this a good signing by the Red Sox?
It gets worse, though.
Dempster has been particularly bad against AL East opponents throughout his career, whether it was last season or in interleague play before that. In 17 starts against the AL East, he's gone 4-8 with a 4.91 ERA.
Not only that, he's been atrocious against the rival New York Yankees, going 0-4 with a 7.62 ERA and 2.05 WHIP, while posting 18 walks in five starts. Last season, he gave up eight earned runs in six innings at Yankee Stadium on Aug. 13.
That's bad enough.
Then, you factor in his two DL stints in 2012 (strained right quadriceps, strained lat muscle) and there's a chance that he misses some time for Boston next season, too.
And remember Josh Beckett (Red Sox fans shaking their heads violently, trying to forget)?
Beckett was a member of the Marlins, with only National League experience, before joining the Red Sox in 2006. Despite having solid numbers with the Marlins, he proceeded to post a 5.01 ERA in his first season at Fenway Park.
The signing of Dempster isn't going to help the Red Sox much. In fact, it may actually hurt them.