INDIANAPOLIS (AP)Rookie quarterback Anthony Richardson will miss at least four weeks after the Indianapolis Colts put him on the injured reserve list Wednesday.

The former Florida star injured the AC joint in his right shoulder when he hit the ground awkwardly at the end of a 4-yard run during Sunday’s win over Tennessee.

Five-year veteran Gardner Minshew will replace Richardson as the starter. Minshew has played in four games this season, relieving the injured Richardson three times. He’s led the Colts (3-2) to wins in two of those relief appearances and his only start, an overtime game at Baltimore.

Colts coach Shane Steichen did not set a timetable for Richardson’s return. He also would not say if Richardson is expected to return this season.

The 6-foot-4, 244-pound Richardson was the fourth overall selection in April’s NFL draft. He has started four games this year but has only finished one.

Sam Ehlinger was the only other quarterback on Indy’s roster until Wednesday when they signed Kellen Mond to the practice squad.

This weekend, Indy visits Jacksonville, where Minshew started his NFL career, in a battle of the AFC South’s co-leaders.