The Rangers have some roster flexibility, so they'll let Beltre rest and have the medical staff take a look at his quad over the next few days before determining early next week whether he can play or needs to go on the DL.
Kevin Kouzmanoff will play in Beltre's absence. Kouzmanoff was added to the roster prior to Wednesday's game in Boston. The Rangers open a series against Houston on Friday at home.
Texas' flexibility with Beltre comes in not having to make a corresponding roster move until starting pitcher Colby Lewis is activated. Lewis has agreed not to take his release, which he could have done per his contract on Thursday if he wanted, because he's been told he'll join the rotation on Monday or Tuesday. This will give Beltre more time to evaluate his quad, which he's never injured before in his career.
Beltre met with Rangers physician Dr. Keith Meister on Wednesday and had an MRI. He appeared to injure the quad hitting a double in the fifth inning of Tuesday's game at Fenway Park. He was taken out shortly thereafter and sent to Texas to see Meister.
"It was not as severe as the concern was originally," general manager Jon Daniels said Thursday. "We're going to play it conservatively."
Beltre, who turned 35 on Monday, has dealt with leg issues for much of his time as a Ranger, though it's mostly been his hamstrings. He did have quadriceps soreness in spring training, though this injury was not in the same area. Beltre missed about a week of spring training and seemed fine when he returned. He was careful about his running and not pressing things too much, something he's monitored for the past few years.
"The quad is new territory for him," Daniels said. "My expectations, in knowing him, he's going to say he's OK and we'll have to determine if he really is. He's so competitive and he wants to go out there. We have to be sure that him playing doesn't risk setting him back."
Beltre, the club's cleanup hitter, has started the season batting .286 with four RBIs.