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Ravens running back Justin Forsett suffered a broken arm in the first quarter of Sunday’s game vs. the Rams.

Forsett’s arm was immediately placed into a cast. He was taken to the locker room and shortly after the team announced the injury.

Rookie Buck Allen figures as the primary back with Forsett out. The Ravens promoted Terrance West from the practice squad last week.

The defenses have dominated early. There’s no score late in the first quarter.