The Zero AIIndianapolis Colts once again needed to turn to their backup quarterback after an injury to Anthony Richardson.

The rookie signal-caller left Sunday's 23-16 win over the Tennessee Titans in the second quarter after injuring his right shoulder on a second-down run.

After Richardson was tackled by Titans outside linebacker Harold Landry, he remained on the ground and tapped his right shoulder as team staffers attended to him. He then went to the locker room for further evaluation.

The Colts initially listed him as questionable to return before ruling him out in the second half.

Richardson, who was the No. 4 overall pick out of Florida in this year's NFL draft, completed 9 of 12 passes for 98 yards before exiting the game.

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Here's the latest on Anthony Richardson's status:

Anthony Richardson injury update

Richardson is believed to have suffered a sprained AC joint, ESPN's Adam Schefter reported, and is set to undergo an MRI to determine the exact nature and extent of the injury.

The Colts next face the Jacksonville Jaguars on the road on Oct. 15.

With Richardson being injured on another quarterback designed run, the staple of the playbook has come under scrutiny.

"I think when you have a dynamic player like him, obviously, one of his skill sets is (as) a runner, (and) that makes him really good," Colts coach Shane Steichen said after the game, according to ESPN. "The designed run that he got hurt on (was) something similar to last week where he popped it for a big one.

"So that's stuff that you've got to look at, be smart with."

Indianapolis Colts' backup quarterback

Backup Gardner Minshew stepped in to replace Richardson after the injury. The fifth-year veteran already stepped in during a Week 2 win against the Houston Texans after Richardson sustained a concussion. He started the following game while Richardson remained in the concussion protocol.