Ed Werder and Jerome Bettis explain how Ben Roethlisberger could be able to play after sustaining a concussion last Sunday. (2:25)

PITTSBURGH -- Ben Roethlisberger said Tuesday that he feels good two days after reporting concussion-like symptoms to the team in Seattle, but the Pittsburgh Steelers aren't ready to throw him back into the lineup just yet.

Coach Mike Tomlin said Tuesday that Roethlisberger suffered "what is now being described as a concussion" and remains in the concussion protocol, as does linebacker Ryan Shazier.

Even as Roethlisberger makes progress, the Steelers won't let him play until he's cleared by doctors.

"We will lean on the expert advice of our medical staff," Tomlin said.

Earlier Tuesday, Roethlisberger said he underwent concussion testing at the team's facility after suffering a traumatic ocular migraine late in Sunday's loss to the Seahawks. Roethlisberger, making his weekly appearance on 93.7 The Fan in Pittsburgh, said he believes he's concussion-free and expects to play Sunday against the Indianapolis Colts.

A source told ESPN NFL Insider Adam Schefter that Roesthlisberger did the radio show just minutes after taking his Impact concussion test, which later confirmed that he had suffered a concussion.

Roethlisberger took a hit from Seahawks lineman Michael Bennett that knocked him down and required teammates to help him up. He played the final nine snaps of the drive but did not return as backup Landry Jones finished the game.

The NFL and the NFLPA are investigating why the spotter and the officials didn't stop play and/or use a medical timeout after the hit that caused Roethlisberger's concussion, sources told ESPN's Dan Graziano. The independent spotter system is supposed to keep players from having to self-report injuries, as Roethlisberger did after he continued to play.

Ben Roethlisberger says he's concussion-free and expects to play Sunday against the Colts. The Steelers, however, say he hasn't cleared the protocol and will not play until he's cleared by doctors. AP Photo/John Froschauer

"I have played through many injuries, but the brain is not an injury you want to play with," Roethlisberger said Tuesday. "When you're done, you want to be a husband or father. And if I have these brain injuries, it's not worth it."

Roethlisberger said he felt like he was looking through water after coming off the field but the vision issues disappeared about 30 minutes after the game. Roethlisberger said he switched helmets about seven years ago and hasn't had a concussion since doing that.

When asked about Roethlisberger's migraine description, Tomlin said, "I'm not a doctor," then emphasized the protocol is ongoing.

"I'm not going to try to get into it," Tomlin said. "I give (Roethlisberger) credit for taking a bite out of that and explaining the circumstances."