That's not to say he's confident of returning to the lineup this week.
"Who knows when I'll be Superman again?" Smith said Monday. "Right now, I'm just Batman. I can't fly."
Smith was inactive for Sunday's loss to the Seattle Seahawks and watched from the sideline before becoming ill in the second half. He was taken to Barnes Hospital for tests, including a CT scan, before being released later that night.
Smith said the illness might have been unrelated.
"They tested me on a couple of different things, but they never said, 'Hey, it was because of your concussion,'" Smith said.
Smith, the second pick of the 2009 NFL Draft, failed two baseline tests last week and wasn't certain when he'd make a third attempt. He won't return to practice until he's been cleared of concussion symptoms, and coach Steve Spagnuolo said the team would not rush Smith back to action.
"We're certainly concerned with Jason," Spagnuolo said. "So we'll make sure everything is done the right way."
Stars including Kurt Warner, Clinton Portis and Ben Roethlisberger sat out on Sunday following concussion-like symptoms. Smith agreed with being cautious, saying he wants to get back in the lineup while adding, "I don't want to die."
"Like in my situation, what good is 310 pounds of twisted steel without a head?" Smith said.
Smith joked that he felt great and described himself as "310 pounds of twisted steel, sex appeal, you know." But he also said all last week he experienced concussion symptoms that appeared to change with the weather and then on Sunday "I felt real bad."
Noise and bright lights in the Edward Jones Stadium didn't help, Smith said.
Smith was injured late in the first half of last week's loss to the Arizona Cardinals. It's the first official concussion of his career, but he has estimated he has had several concussions -- including perhaps a few just in his first NFL training camp.
"Linemen get concussions all the time, you go out and keep playing," Smith said. "You get hit helmet to helmet all the time and you get a little woozy."
"I don't recall blanking out, I just remember being real woozy and 'Uhhh, something's wrong, uhhh, something's really wrong.'"
The Rams (1-10) played much of Sunday's game minus three offensive line starters, with center Jason Brown sidelined by a sprained right knee in the second quarter and guard Richie Incognito out for a fourth straight game with a ligament injury to his right foot. Coach Steve Spagnuolo said is hopeful both Brown, whose injury was described as moderate, and Incognito will practice Wednesday.
Copyright 2009 by The Associated Press