Cooper underwent an MRI on his knee Wednesday after suffering an injury in practice last week and re-aggravating it during the team's win over the New York Giants on Monday, Archer reports.
He will not practice Thursday and is set to meet with doctors about the MRI results.
The three-time Pro Bowler tweaked his ailing knee in the first half of Monday Night Football and exited briefly in the second quarter. He returned shortly thereafter and went on to score a 45-yard touchdown in the fourth.
Cooper downplayed the injury postgame, saying it "wasn't anything that was that bad," and that his knee simply "locked up," according to The Dallas Morning News' Michael Gehlken.
The Alabama product has been a revelation since going to Dallas in a trade with the Oakland Raiders last year. The fifth-year pro has compiled 1,426 yards and 12 touchdowns on 95 receptions in 17 games since joining the Cowboys.