"He's really sick," Francona said Wednesday. "Doctors are trying to figure it out. I have not seen him this morning. He wasn't good yesterday and we'
re going to have to play this one by ear. There are some pitchers, because of the off-day, that we're actually OK."
Francona had said Tuesday that Beckett would be able to throw on the side ahead of Saturday's start and have a relatively normal week. That now seems optimistic.
"We'll see how he responds [Thursday]," Francona said. "He just has a good old-fashioned case of the flu."
In case Beckett can't pitch Saturday, lefty Andrew Miller is set to throw a shorter side session Thursday in case he's needed to start in Beckett's place.
Also, right-handed reliever Bobby Jenks will throw a side session Thursday and increase his workload to more than the 20-pitch session he tossed Tuesday.
Francona said Jenks has made "really rapid steps" in the past three or four days. If he responds well after Thursday's extended session, the team and the medical staff will make a decision where Jenks goes from there.
Injured shortstop Jed Lowrie is in Los Angeles and will have his left shoulder examined Wednesday by Dr. Lewis Yocum. Francona said there could be an update on Lowrie's condition following Wednesday's game.
Joe McDonald is a reporter for ESPNBoston.com.