An MRI on Adrian Beltre's leg revealed a Grade 1 strain to his left quadriceps muscle.
Beltre won't be place on the disabled list immediately. He and the Rangers will wait through the weekend to decide if a stint on DL is necessary, according to Jeff Wilson of the Fort Worth Star-Telegram.
General Manager Jon Daniels has told reporters that the mild strain is "not as severe as feared."
The delay on a decision concerning Beltre means that Colby Lewis won't be able to make his scheduled return to the rotation Saturday. Beltre would take Lewis's spot on the DL. Lewis will pitch in a MLB game for the first time since 2012 on either Monday or Tuesday.
Beltre left Tuesday's game in Boston with soreness in the quad, and flew back to Texas to have his leg examined.
Josh Wilson filled in for Beltre at third base in the final four innings Tuesday and in Wednesday's game. Kevin Kouzmanoff was recalled from Triple-A Round Rock, and recorded a pinch-hit single in the seventh inning Wednesday. Wilson and Kouzmanoff will likely share the third base responsibility in Beltre's absence.
Beltre has a .286 batting average for the young season.