Mason Rudolph remains in the league’s concussion protocol. The Steelers’ medical staff remains under scrutiny.

Two days after the Pittsburgh quarterback absorbed a brutal hit from Ravens safety Earl Thomas, coach Mike Tomlin is still trying to explain why Rudolph was allowed to walk off the field, rather than be escorted out on a cart.

The team’s medical staff brought out a medical cart to remove Rudolph, but it malfunctioned before he could be transported. Though a second cart was available, the Steelers didn’t use it, at Rudolph’s request.

“There are two carts in our stadium — there’s probably two carts in every stadium. He walked off the field because he chose to walk off the field, and the medical experts were comfortable with his ability to walk off the field and the safety in it,” Tomlin began Tuesday. “Whether or not the cart was functioning is irrelevant to the fact that he walked off the field. To be quite honest with you I didn’t know that the cart wasn’t functioning until after the game because I was more concerned with Mason.”

The NFL released a statement that the team wasn’t required to use a cart, even though Rudolph was knocked unconscious and later hospitalized.

“A cart was brought on the field in the event it was needed,” the statement said. “After evaluating the player, medical staff determined a cart was not necessary in this instance. Had one been needed, there was a backup cart on the other sideline which was immediately available. He received appropriate medical care per gameday protocols, and is now in the concussion protocol.”

Undrafted rookie Devlin Hodges replaced Rudolph, and completed 7-of-9 passes for 68 yards, in the overtime loss to Baltimore. Hodges, who played at Samford and was re-signed to Pittsburgh’s practice squad on Sept. 10, is expected to start Sunday night against the Chargers.