Beckett's back was stiff Wednesday, four days after he felt spasms while warming up for his start against the Florida Marlins. He left the game before it even started.
The Red Sox leave next Wednesday for Tokyo, where they have two exhibition games against Japanese teams before playing the first two games of the regular season against the Oakland Athletics on March 25 and 26.
All signs point to Beckett staying behind, although the team has made no official announcement.
"I'm not that concerned about making a statement about Japan," Boston manager Terry Francona said Wednesday. "That's not what is driving us. Just trying to get him healthy."
He said Beckett was stiff Wednesday after stretching and exercising Tuesday.
"The big thing I stressed to him is that the timetable is that there is no timetable. It's when he's healthy, and that's all I want him to worry about," Francona said.
Schilling is rehabilitating his right shoulder and is expected to be sidelined at least until the All-Star break. But the Red Sox have public appearances scheduled in Japan, which Schilling could attend if he goes.
"I think he wants to go," Francona said. "Some of our thinking is we aren't sure it's in his best interests. That's what we care about. The appearances and things like that, that's secondary for what we're trying to do here."
He gave no update on any progress Schilling may have made in his rehab.
"He continues to try and get stronger six days a week. Just going at it," Francona said.
Bartolo Colon makes his first appearance on Thursday against Tampa Bay since Boston signed him to a minor league contract on Feb. 25. Shoulder and elbow problems limited him to 29 games the past two seasons, the last two in his four-year contract with the Los Angeles Angels. "I have not seen him" pitch in spring training, Francona said. "Just the fact that we're getting him on the mound is exciting." ... The Red Sox assigned reliever Dan Kolb to their minor league camp. Francona said he told non-roster infielders Keith Ginter and Joe Thurston that they would be sent there before the trip to Japan. ... SS Julio Lugo, who has played in only two games because of a back injury, probably will return Friday against Baltimore, Francona said.