The severity of the issue isn't yet known, but Beckett will be eligible to rejoin the Red Sox before the end of the month. It's another tough blow for a team that is having troubling digging their way out of the cellar in the American League East.
Clayton Mortenson will take Beckett's place on the roster.
The 33-year-old Beckett has not pitched well for the Red Sox this season, as he sports an ERA over 4.00. The most notable of signs is his fastball velocity, which is down from a career average of 94, at 92 miles per hour.