According to Matt Maiocco of CSN Bay Area – citing a 'league source' – the San Francisco 49ers have placed S Antoine Bethea on season-ending IR.

Bethea was at Stanford today having an MRI on the shoulder/chest area that he injured in Thursday night's loss to the Seattle Seahawks.

Bethea, who has started all seven games this season, had 44 combined tackles and a sack for the season. He has been to three Pro Bowls.

The move will make room for WR Jerome Simpson to join the active roster. Simpson is coming off of a six-game suspension and became eligible to rejoin the team for practices on Monday. However, with a shortened week, he was not activated for the team's game against the Seahawks.

The 49ers had until 1 PM on Friday to make a roster move to fit Simpson on the active roster.

Update:

Bethea's injury is actually a torn pectoral according to Matt Barrows of the Sacramento Bee.