Junior Vondrell McGee left Saturday's 38-14 victory over Colorado in Austin during the second half with an injured left shoulder, and freshman Tre' Newton suffered a mild concussion in the first half.
Texas' ground game struggled against the Buffaloes (1-4), who limited the Longhorns to 46 yards rushing.
Texas (5-0) trailed 14-10 at halftime before taking control behind their defense and special-teams play.
"We're trying to get better in the running game and it didn't work," coach Mack Brown said after the game. "We've just got to keep looking at it."