Ross left after the collision and was later diagnosed with a left quad contusion. Jarrod Saltalamacchia came on in his place.
Though Middlebrooks grimaced, he was able to stay in the game initially. But when the Red Sox went out for defense in the top of the seventh, Pedro Ciriaco replaced Middlebrooks at third.
Middlebrooks sustained what the Red Sox called "right side pain."
By game's end -- a 6-1 loss to the Twins -- Middlebrooks had been sent out for X-rays and a CT-scan with the hope that he doesn't have a significant rib or oblique injury.
Results were not available by the time Boston's clubhouse closed after the game.
"Again, when he slid on his side, he kind of whipped over and slammed into the wall there," said Red Sox manager John Farrell. "As a precaution, we took him out of the game. He took the next at-bat and he didn't feel anything. His right side hit the wall."
Ross is confident his injury is nothing to worry about.
"Obviously I'm a little sore," Ross said. "I think I just jammed the top of my kneecap. It's pretty sore, and there's some swelling in there. If I wasn't a catcher, I think I'd be fine, but squatting is a little bit sore."
How did Ross see the play evolve?
"It happened so fast," he said. "I didn't watch the replay. Everybody told me my shinguard, as I hit the ground, folded over on my knee and hit the dirt pretty hard. It's right on top of my knee. It's kind of funny. They said there's no real angle where you actually see it. I just jammed it into the ground pretty hard."
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.