Murray's diagnosis of an injury he suffered on the opening kickoff of the Big 12 Championship Game against Missouri is now more serious than the original one.
He was originally thought to have only bruised his left knee, which left him on the sidelines for the rest of the game.
The MRI taken on Dec. 8, however, shows that Murray actually ruptured a tendon in his left hamstring, which will require surgery.
And the Sooners plan to have the surgery immediately on Dec. 22, according to university officials.
"Obviously, we're very disappointed for DeMarco," said OU head coach Bob Stoops. "He has been an important part of our success this year and we will miss his contributions. DeMarco has had an incredible year."
After battling back from his knee injury last season, Murray finally hit his stride midway through the season when he torched Kansas State for 104 yards on the ground and 63 receiving yards on four receptions, and he had four touchdowns—two receiving, two rushing—in that contest.
Murray is the Sooners' second-leading rusher with 1,002 yards this year, just eight yards behind junior running back Chris Brown.
But the effect is even greater than on the ground in the Sooners' offensive scheme.
He gives the Sooners an explosive option to turn to for big plays both on the ground and in the air.
Murray leads the team and ranks second in the Big 12 Conference with 2,171 all-purpose yards and ranks third in the nation.
In addition to his 1,002 rushing yards, he has also accumulated nearly 400 receiving yards and has amassed 774 kickoff return yards.
And Murray knows how to find the end zone.
He has scored 18 touchdowns this year, second on the team, and ranks third in points scored for the Sooners with 108.
Given his offensive production, the Sooners will be without a definite explosive option in their offense.
As far as his return, he will be out five months before he will be able to resume training, according to trainer Scott Anderson.