The potential news feared by Clemson’s football program was confirmed on Thursday, as B samples from the three Tiger football players who had tested positive for a banned substance last week also showed trace amounts of ostarine, an illegal muscle-growth supplement.

That means the three players, including star defensive lineman Dexter Lawrence, were officially ruled out for Saturday’s College Football Playoff semifinal against Notre Dame.

Lawrence, reserve tight end Braden Galloway and reserve offensive lineman Zach Giella will be unavailable for Clemson’s Cotton Bowl matchup with the Fighting Irish. Clemson Athletic Director Dan Radakovich confirmed Thursday that the players would not be able to play and said the school would not comment further as it considered its options.

The program first learned of the positive tests last week. On Tuesday, Coach Dabo Swinney said he would wait for the B sample results to come back before ruling the players out of Saturday’s game.

The three players face a suspension of up to one year, pending appeal. This might not be of particular importance to Lawrence, who is eligible for the NFL draft after this season and is projected as a first-round pick. The 6-foot-4, 345-pound lineman is an integral part of the Tigers’ vaunted defensive line, joining fellow draft prospects Christian Wilkins and Clelin Ferrell in the trenches.

“We get tested regularly and we know not to do anything stupid or selfish like that,” Lawrence said to reporters at Thursday’s media day. “That’s why this is such a shock.”

The junior defensive lineman was not required to address the media ahead of the Tigers’ Cotton Bowl matchup but asked to anyway. He added that he has not made a final decision about the NFL.

According to the USADA, the number of positive athlete tests containing ostarine has increased steadily in recent years. The substance is prohibited by the World Anti-Doping Agency and is not approved for human consumption or use in the U.S. Because of that, it is not found in any food or legal medical treatments.

The Post and Courier reported that Clemson has launched an in-house investigation to determine how the substance could have entered the players’ systems.

Clemson will face Notre Dame on Saturday at 4 p.m. Alabama takes on Oklahoma in the other semifinal at 8 p.m. The winners of those games will meet on Jan. 7 to play for the national championship.