Updated

Carl Crawford has a sprained ligament in his throwing elbow and the Boston Red Sox left fielder will remain sidelined for a while.

The team released a statement Thursday night saying Crawford's diagnosis was made by the Red Sox medical staff and confirmed by Dr. James Andrews. Crawford received a Platelet Rich Plasma injection and will be shut down from baseball activity "during the initial phase of his treatment."

The club did not announce a timetable for Crawford's return, but he is expected to miss at least another month or two — maybe more.

"It is what it is what it is," Red Sox manager Bobby Valentine said. "We'll just let Mother Nature to take the time to heal him up and get him back. I don't know how to explain it or put it into my thought. I wish he was 100 percent. Not playing for a while is going to kill him more than it's killing me."

The Red Sox were already short-handed in the outfield because of an injury to All-Star center fielder Jacoby Ellsbury, who finished second in the voting for AL MVP last season. Ellsbury is expected to be out until June because of a right shoulder injury sustained against Tampa Bay on April 13.

Boston acquired outfielder Marlon Byrd from the Chicago Cubs on Saturday to help fill the void. Byrd hit just .070 (3 for 43) with Chicago, but collected his fifth hit in four games for the Red Sox on Thursday night in a 10-3 victory against the White Sox.

Crawford was largely viewed as a disappointment last year when he hit .255 with 11 homers, 56 RBIs and 18 stolen bases in his first season with Boston after signing a $142 million, seven-year contract as a free agent. He is yet to play in the big leagues this season.

Over the previous eight seasons, the 30-year-old Crawford hit above .300 five times for Tampa Bay, leading the American League in stolen bases four times. In his last season before coming to Boston, he batted .307 with a career-high 19 homers, drove in 90 runs and stole 47 bases.

Crawford also was shut down during spring training after experiencing inflammation that stemmed from offseason surgery on his left wrist. He remained at the team's training complex in Florida after the club broke camp and participated in extended spring training games.

When the soreness in his left elbow lingered, Crawford traveled to Birmingham, Ala., to be examined by Andrews, a noted specialist in elbow injuries.

Crawford was diagnosed with a sprained ulnar collateral ligament.

Lars Anderson, normally a first baseman, started in left field for Boston against the White Sox on Thursday night. Anderson played 571 of his 578 minor league games and his first 25 big league games at first base.