Indianapolis Colts quarterback Anthony Richardson (5) Marc Lebryk-USA TODAY Sports

Indianapolis Colts quarterback Anthony Richardson suffered a shoulder injury during Sunday’s game against the Tennessee Titans, and the rookie may be sidelined for a significant period of time.

Richardson is believed to have a Grade 3 sprain of his AC joint, Ian Rapoport of NFL Media reports. If an MRI on Monday confirms the diagnosis, Richardson will likely be out for at least a month.

The injury is to Richardson’s right shoulder, which is his throwing shoulder. That obviously complicates matters further.

Richardson landed hard on his right shoulder when he was tackled on a designed run play in the first half of the Colts’ 23-16 win over Tennessee. He appeared to be in significant pain as he was taken to the locker room.

The injury on Sunday was one of several that Richardson has suffered this season. He was shaken up on a scramble play in Indy’s game against the Jacksonville Jaguars in Week 1 and left late. The following week, Richardson took a big shot on a touchdown run and sustained a concussion. He sat out in Week 3.

While Richardson has shown flashes of having huge potential, all of the injuries are a reminder of the difficulties dual-threat quarterbacks face in the NFL.

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