Alabama could be without one of its top defensive players for Monday’s College Football Playoff national championship matchup against Clemson.

During media day on Saturday, Nick Saban said that star linebacker Christian Miller is questionable for Monday night’s showdown. Miller suffered a hamstring injury in the second half of the Crimson Tide’s Orange Bowl victory over Oklahoma on Dec. 29.

Miller has been a key contributor to Alabama’s defense all season long. The linebacker has played in all 14 games this year, totaling 36 stops, 11.5 tackles for loss and 8.5 sacks.

Alabama’s defense ranks in the top 25 nationally in most major statistical categories.

If Miller doesn’t participate on Monday night, he’ll mark the second significant absence from the national title bout. Clemson defensive lineman Dexter Lawrence will also miss the game due to a failed NCAA drug test.

Lawrence also missed the Tigers’ Cotton Bowl game against Notre Dame.

Monday will mark the fourth consecutive year that Alabama and Clemson have met in the College Football Playoff. It will be the third time the two teams have met for the national championship.

Both teams enter the game 14-0.