"He's still having symptoms with the concussion," manager John Farrell said. "The foul tip the other day in Baltimore kind of brought some of those symptoms back."
A concussion also sidelined Ross from May 12-24 after he took a pair of foul balls off his catcher's mask on May 11 against Toronto. Ross is hitting .185 this season with two doubles, four home runs and six RBIs.
To fill his roster spot, right-hander Alex Wilson was recalled from Pawtucket. This will be his third stint with the Red Sox this season. In 17 appearances, he's 1-1 with a 2.61 ERA.
Michael Periatt is an associate reporter for MLB.com. Follow him on Twitter @Michael Periatt.