Though it's believed to be just a nagging injury, there's no reason for the Red Sox not to play it safe at this juncture of the season.
It sounds as if Ellsbury won't return until Tuesday at the earliest, when the Red Sox follow an off-day by hosting the Rays for the opener of a two-game series.
"Oh gosh, I have no idea," Valentine said. "We'll probably be conservative and cautious. But when he's ready to play, we'd love to have him play."
Would Ellsbury be playing if the Red Sox were in contention?
"I'm not sure," Valentine said. "It's something, I think, he wants to be cautious with."
Scott Podsednik played center in Ellsbury's absence.
Whatever the injury is, it hasn't impacted Ellsbury's play. Over his last four games, he's 7-for-15 with six RBIs.