Beltre, who played in Tuesday's All-Star Game, got an MRI on Thursday, with preliminary reports showing no damage to his hamstring, manager Terry Francona said.
"I just think with the travel, I didn't have a real good feeling running him out there," Francona said. "Knowing the way he plays, I don't want to let him hurt himself."
Beltre participated in running drills before Thursday's game, and Francona said that the veteran third baseman could possibly be available in a pinch-hit situation, yet in the best-case scenario, would be available to play Friday.
"It is not as bad as people thought. A couple of days and I should be ready to go," Beltre said. "I was ready to play, but he [Francona] wouldn't let me. I did some exercises today to get it to be stronger and be the best we can be."