Bailey, along with starting pitcher Josh Beckett, were both in Cleveland on Tuesday having their thumb injuries examined by specialists, mlb.com reported.
While there was optimistic news on Beckett, Bailey's prospects were uncertain, Red Sox manager Bobby Valentine told reporters before Boston's exhibition game against the Nationals in Washington.
Valentine said the Sox are "totally" expecting Beckett to make his start on Saturday in their season-opening series against the Detroit Tigers, but general manager Ben Cherington told reporters Bailey might not be on the Opening Day roster.
"We're proceeding as if not going to be on the roster Opening Day," Cherington told The Boston Globe.
"But until we get more information, I won't speculate on what may or may not happen. It's clear he has an injury and we're still trying to figure out the best way we're going to deal with it."
When asked if Bailey could be out days, weeks or months, Valentine said it's "possibly all of the above."
If Bailey is sidelined, Mark Melancon or Alfredo Aceves seem to be the most likely candidates to serve as Boston's closer.
"I think it will evolve early in the season," said Valentine about who might fill in for Bailey.
(Reporting by Larry Fine in New York; Editing by Frank Pingue)