The Indianapolis Colts have placed Anthony Richardson on injured reserve with a sprained AC joint in his right shoulder, keeping the rookie quarterback out for at least four games.

In Sunday's 23-16 win over the Tennessee Titans, Richardson was hurt with just over 4 1/2 minutes to go in the second quarter when he was tackled on a 4-yard run. He took a hit to the left shoulder but appeared to land awkwardly on the right one.

Gardner Minshew will start Sunday against his former team as the Colts visit the Jacksonville Jaguars in a matchup of teams tied atop the AFC South with 3-2 records.

Richardson has made four starts since the Colts drafted him fourth overall in this year's draft, but the dual-threat QB has only been able to finish one game as injuries have forced him out of the other three.

Colts place QB Anthony Richardson on IR, will be out for next four games. pic.twitter.com/SeGnFimqP6

— NFL (@NFL) October 11, 2023

In the Colts' 31-20 victory over the Houston Texans in Week 2, Richardson suffered a concussion when he took a hard hit to the head at the end of a 15-yard touchdown run. He was unable to clear the NFL's concussion protocol and Minshew led Indianapolis to a 22-19 overtime win over the Baltimore Ravens in Week 3.

Richardson returned for Week 4's overtime loss to the Los Angeles Rams - the first game of his young career he was able to complete.

Richardson also suffered a knee bruise on a hard hit near the goal line in the final minutes of a 31-21 season-opening loss to the Jaguars. Colts coach Shane Steichen said Richardson could have returned, however, and he was taken out as a precaution.

On the season, Richardson has completed 59.5 per cent of his throws for 577 yards with three touchdowns and one interception for an 87.3 passer rating. He has also rushed for 136 yards and four TDs.

Minshew has completed 68.7 per cent of his passes for 553 yards with two TDs and no picks for a 95.1 rating.