The right-hander from Gibsons, B.C., said he will not pitch this season for physical reasons and the fact he wants to spend more time with his kids.
“I don’t feel like I am capable of performing to the ability and standard that I am accustomed to. I feel it’s in the best interest of both the club but most importantly myself to step away from playing baseball at this time. The time is right,” Dempster told FOXSports.com.
“I’m not saying retirement but I definitely won’t be playing this season.”
Dempster, who won eight games in 29 starts last season before Boston moved him to the bullpen late in the regular campaign and for the playoffs, was expected to battle Doubront for the fifth spot in the rotation behind Jon Lester, Clay Buchholz, John Lackey and Jake Peavy.
The Red Sox are expected to place Dempster on the restricted list, meaning he would not collect his 2014 salary of $13.25 million US.
The 36-year-old signed a two-year, $26.5 million deal with Boston in December 2012.
Dempster had spent the previous eight-plus seasons with the Chicago Cubs as a starter and relief pitcher before they traded him to Texas on July 31, 2012 for a couple of minor leaguers.