St. Louis Rams quarterback Marc Bulger, who is sidelined by the second right shoulder injury of the year, could miss the rest of the season, team and league sources confirmed. Bulger was knocked out of Sunday's game against the Arizona Cardinals by a shoulder injury and concussion. An MRI exam on Monday revealed that, while there is no significant structural damage to Bulger's throwing shoulder, there is more swelling in the joint than occurred with a similar injury earlier in the season. The St. Louis Post-Dispatch cited an unnamed Rams official as acknowledging Bulger will "be out quite a while." Three sources told ESPN.com that is an accurate assessment. The original diagnosis was that Bulger would miss two games, but that now seems to be overly optimistic. At 4-6, the Rams' playoff hopes are waning. The team might be reluctant to have its star quarterback return in December and risk further damage to his shoulder, if postseason chances are slim. Journeyman Jamie Martin, who is suffering from bruised ribs, will take over the starting spot. Rookie Ryan Fitzpatrick of Harvard, a seventh-round draft choice, might also get some playing time in the final six games.