An industry source said Saturday that doctors are trying to determine whether Ellsbury has a deep bone bruise or fracture in his right foot, the result of fouling a ball off his foot Aug. 28 in a game at Fenway Park.
Ellsbury aggravated the injury Thursday night when he stole second base in the 10th inning of Boston's 9-8 win over the New York Yankees and did not respond to treatment Friday, according to manager John Farrell.
Ellsbury returned to Boston and underwent an examination an MRI on Saturday morning and was scheduled for additional testing, Farrell said. He also is scheduled to go to Denver to see Dr. Thomas Clanton of the Steadman Clinic for a second opinion.
"I don't think we're looking at something that is just day to day here," Farrell said Saturday. "But before we get into any kind of time frame, I think what's probably best for all involved here is to wait until we get more conclusive evidence and information."
The injury involves the navicular bone, the same bone that Red Sox second baseman Dustin Pedroia fractured in his left foot with a foul ball in San Francisco in 2010. Pedroia was placed on the disabled list the next day, June 26, returned to play two games in August before returning to the DL for the rest of the season. He had surgery in the offseason in which a screw was inserted to promote healing.
The Red Sox recalled Jackie Bradley Jr. from Triple-A Pawtucket and started the rookie in center field for Saturday's game against the Yankees.
"We'll probably go day to day for the time being," Farrell said regarding Boston's outfield alignment.
Ellsbury, who leads the majors with 52 stolen bases, was batting .299 with a .355 on-base percentage. The speedster was batting .320 (24 for 75) in his last 17 games, with eight stolen bases in that span.
"Let's not kid ourselves," Farrell said. "Jacoby Ellsbury in the leadoff spot, with the stolen-base ability, the talent that he has -- this is a guy we're going to miss for the time being that he will be out."
The injury initially occurred in the seventh inning of the Aug. 28 game against the Orioles, when Ellsbury fouled a pitch off the top of his right foot, just below the shin guard. He remained in the game, beat out an infield hit, stole second and came around to score the game-tying run on a base hit by Pedroia.
Ellsbury did not take the field the next inning, but a fluoroscan taken of the foot came back negative, Farrell said, and Ellsbury was back in the lineup the next night.
Ellsbury played in the next five games before sitting out last Tuesday's game against the Tigers because of a swollen left thumb. He then started the next two games before sitting out Friday night.
"[Ellsbury] is frustrated," Farrell said. "He wants to be on the field. He feels like he can play right now. But at the direction of the medical people, we have to be careful with this.
"I can tell you this: Jacoby wants to be on the field. He's kind of [ticked] he's not here right now, to be honest with you."