"He's still fighting some back stuff," said general manager Ben Cherington. "He's probably going to miss a little time."
Victorino returned on July 19, but he exited Wednesday's game in the fifth inning with discomfort.
Newcomer Yoenis Cespedes, acquired in a blockbuster for Jon Lester, will probably get a lot of action in right field while Victorino is out.
A key performer for the Red Sox last season, Victorino has played in just 30 games in 2014. He has one more year left on his contract.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.