St. Louis Cardinals third baseman Scott Rolen has a separated left shoulder. He will have an MRI on Thursday to determine the severity of the injury and how much time he will miss. Rolen suffered the injury during the fifth inning of Tuesday's loss to Los Angeles when he collided with Dodgers first baseman Hee Seop Choi while running out a ground out to the pitcher. Rolen was initially diagnosed with a sprain. However, team doctor George Palleta announced after Wednesday's 9-3 win over the Dodgers that Rolen suffered a separation and that more will be known on Thursday after an MRI has been performed. The All-Star could miss as little as two weeks or as much at three months. The injury is unrelated to the separation he suffered during the 2004 playoffs, as it occurred in a different joint of the shoulder.