By Madison Williams The severity of his injury is unknown, but the pitcher could miss time if the evaluation shows any substantial damage. View the original article to see embedded media. One of the defending World Series champion Braves’ key relievers, Luke Jackson, could miss time this season due to a right arm injury. The MRI showed damage to his “ulnar collateral ligament in his right arm,” the Braves posted on Twitter. As a right handed pitcher, the severity of the injury could cause Jackson to miss substantial time depending how evaluations of the damage come back. In last year’s World S…