INDIANAPOLIS -- Colts quarterback Anthony Richardson will miss Sunday's game after sustaining a concussion in Week 2, coach Shane Steichen said Friday.
Backup Gardner Minshew will start the road game against the Baltimore Ravens, with Sam Ehlinger serving as his backup.
Richardson did not practice this week after self-reporting concussion symptoms in the second quarter of Sunday's victory over the Houston Texans. It's believed he sustained the injury on a 15-yard touchdown run in the first quarter, during which he hit his head after being tackled as he crossed the goal line.
A source told ESPN's Jeremy Fowler that Richardson is optimistic about playing in Week 4 against the Los Angeles Rams, assuming he passes through the protocol. The Colts and Richardson have been cautious this week in their discussions about his return.
Richardson, the No. 4 overall pick in this year's draft, has already had a couple of injury issues, bruising his left knee during a Week 1 loss to the Jacksonville Jaguars and missing the final few plays of the game.
Minshew started two games in Philadelphia last season, when Steichen was the Eagles' offensive coordinator. The Eagles went 0-2 in those games, with Minshew completing 58.3% of his attempts and throwing for 629 yards on 42-of-72 passing with three touchdowns and three interceptions.
"He's been in these situations," Steichen said. "Obviously, he got a lot of work this week, so he'll be prepared and ready to go."
Minshew had competed for the starting quarterback job during the offseason before Richardson ultimately was named to the role.
The Colts will also be without center Ryan Kelly, who sustained a concussion against Houston as well. Indianapolis will likely look to Wesley French, who took Kelly's place against the Texans.
Richardson has completed 63.8% of his passes for 279 yards with one touchdown and one interception and has three rushing TDs.