Dempster, who turns 36 next season, joins the Red Sox on a two-year, $26.5 million deal. He'll wear No. 46, which previously belonged to Franklin Morales.
"The Red Sox were extremely kind and gracious," Dempster said. "I kind of had that feeling that they wanted me as much as everyone out there. I was so excited to come here and have a chance to play with such a storied and great organization."
Dempster will likely slot into the rotation behind Jon Lester, Clay Buchholz and John Lackey. The Red Sox have seen firsthand the trouble that health issues in the rotation can cause, and that's part of what made Dempster appealing.
Dempster has been a National Leaguer for all of his 15-year career besides the second half of last season, when he was with the Rangers. He's been consistent, too. The right-hander has carried an ERA of 3.85 or lower four times in the last five seasons, and he's thrown at least 200 innings seven times in his career -- including four straight years from 2008-11.
"That's your responsibility as a starting pitcher in the big leagues," Dempster said of taking up all those innings. "The norm used to be 300, and somehow we've worked it down to 200, and even 180 seems to suffice. I'm a guy who wants to go out there. I work extremely hard during the offseason and season to keep myself as healthy as I possibly so I can take on that workload. It's something I pride myself on. As a starting pitcher, we only get to contribute one out of every five days."
That was a point of appeal for Sox general manager Ben Cherington, too.
"The consistency that he's shown in terms of taking the ball every fifth day was important to us," Cherington said. "As a team, when you start having to fill in for guys, if we don't have a reliable rotation and you start to fill in with guys from down below or moving guys from the bullpen, you're inevitably weakening another area of our team. It's no secret that our best teams generally have been ones where we've had pretty good reliability in the rotation. We're certainly trying to build that again here."
Dempster's addition doesn't mean the Red Sox are done shaping the rotation, though. Smaller signings like Aaron Cook and Vicente Padilla ended up having an impact in 2012, and once the new year arrives, similar Minor League deals will likely be reached.
"Well, we have a number of guys that are proven winners at the Major League level," Cherington said. "Certainly Lester, Buchholz, Dempster, Lackey, [Felix] Doubront, who had a really promising first full season. And then other guys on the team who are capable of pitching in that role: Franklin Morales, [Alfredo] Aceves has done it some. I also think our depth underneath is improved compared to where we were a year ago; guys that were sort of getting toward the top of the system and could be options at some point during the 2013 season.
"I think we're in solid shape, but we're always open-minded about ways to improve. I've said it before, [and] I'll say it again, we're excited to have Ryan Dempster here. The performance of the other guys who are already here is going to have a bigger impact on our overall rotation performance than any one player we were going to add."
The largest question surrounding Dempster is the adjustment not just to the American League, but the AL East. Dempster's time in Texas didn't go as planned. After posting a 2.25 ERA with the Cubs, he had a 5.09 mark with the Rangers. That included 10 home runs in 69 innings. Dempster allowed one fewer home run (nine) in a lot more innings with the Cubs (104).
"Obviously the first half of the season went extremely well," Dempster said of his time in Chicago, where he was the Opening Day pitcher the last two years. "Once I got over to Texas, after a few starts, I really seemed to get on a roll and pitch well. ... You're facing a DH instead of a pitcher. Whether people admit it or not, aside from probably about 10 pitchers, there is that little bit of a break at the bottom of the lineup where you get to face a pitcher. You still have to make your pitches and get outs, but I'd much rather sit there and face a pitcher than have to pitch against a David Ortiz, that's for sure. That's probably the bigger test. You have to maintain your focus. Once you do that, it's just about making pitches."
Dempster, who's from Canada, didn't reveal if he'll pitch in the World Baseball Classic, but he said the Sox will be his first priority.
Dempster had a 43.5 percent ground-ball rate, 51st best among Major League starters, according to FanGraphs. His fastball appears to have dropped into the 89-mph range on average, whereas he sat in the 90-mph range the previous three seasons, according to the site.
To make room for Dempster on the 40-man roster, right-handed pitcher Pedro Beato was designated for assignment.