Clemson will be without star defensive lineman Dexter Lawrence and two other players for Saturday's Cotton Bowl after their B-samples came back positive for ostarine, athletic director Dan Radakovich said in a statement, according to ESPN's David Hale.
In addition to Lawrence, tight end Braden Galloway and offensive lineman Zach Giella will also be suspended for the game.
On Monday, coach Dabo Swinney told reporters the players had a "sliver of ostarine" in their initial tests and they all thought it was a joke because none of them intentionally consumed the substance.
The players could be suspended up to a full year, pending an appeal. The Tigers have already been preparing for Saturday's College Football Semifinal with the expectation Lawrence would not play.
"We get tested regularly and we know not to do anything stupid or selfish like that," Lawrence told reporters Thursday, according to ESPN. "That's why this is such a shock.
"I'm just in the moment trying to help the team the best I can and be the leader I've been all year. Just right now I'm doing it behind the whistle."
Clemson is 13-0 this season and will face the 12-0 Fighting Irish for a trip to the national championship. The Tigers are looking to win their second title in three years.