Coach Bob Stoops announced Thursday that Green-Beckham was added to the Sooners' roster after signing a financial aid agreement Wednesday. He can immediately enroll in classes and begin team activities.
He would be eligible to play beginning in 2015.
Green-Beckham caught 59 passes for 12 touchdowns as a sophomore last season at Missouri and was one of the top prospects in the nation when he signed with the Tigers. He was dismissed after being charged in October 2012 with marijuana possession in Columbia, Missouri, and later pleading guilty to trespassing.
Stoops said in a statement that Green-Beckham ''understands the privilege and responsibilities of representing the Oklahoma football program.''