Indianapolis Colts' rookie quarterback Anthony Richardson was ruled out for the remainder of Sunday's game against the Houston Texans due to a concussion.
Richardson, who scored a 15-yard touchdown in the first quarter, was later medically evaluated and officially declared out for the rest of the match.
Gardner Minshew stepped in as his replacement.
Richardson took a hit to the back of his head during his touchdown run, but it remains unclear whether this was the cause of his concussion.
He participated in two more Colts possessions before being taken to the medical tent and then to the locker room for further evaluation.
In addition to Richardson, Colts' starting center Ryan Kelly was also ruled out with a concussion in the second half of Sunday's game.
This adds further concerns for the Colts, who have already been plagued by a series of injuries this season.
Richardson's ability to run the ball has been a topic of discussion, especially since the Colts often use him as a runner.
Coach Shane Steichen stated earlier in the week that most quarterbacks actually get injured in the pocket rather than while running.