Maddox was trying to elude Titans safety Lance Schulters, and completed a pass to Amos Zereoue as he fell. Titans linebacker Keith Bulluck, trying to finish off the play, hit Maddox with his arm as the quarterback was headed down.
Maddox's head and neck hit hard on the ground, and he lay motionless as trainers, doctors and emergency medical personnel tended to him. "I couldn't even see what happened," Bulluck said afterwards.
He was transported via ambulance to Baptist Hospital's Trauma Unit after about a 15-minute delay.
A Steelers spokesman said Maddox, who had lost feeling on the field, had regained some sensations and movement in all his limbs. He was kept overnight in the hospital and diagnosed to have a concussion and a spinal contusion. He has fully regained feeling in all of his limbs.
Players on both sides were concerned for Maddox, whose ascent to stardom after three years out of football and stints in the Arena League and XFL, had been perhaps the NFL's biggest story this season.
"You wanna see some sign, a hand moving, something, and when you don't see that, it's tough, real tough," Steelers guard Alan Faneca said of the scene on the field.
"I've been in that position twice, being carried off the field, and there's nothing good about it," said cornerback Samari Rolle, who twice has had neck injuries in his career. "Football is a physical game, and I hope he's OK."
"You just pray he's OK. You pray for his family, because you know they're going through a lot right now, because they're either seeing it on TV or hearing it on radio," Titans receiver Derrick Mason said. "Whether it be his wife or his children, they're going through a lot right now, so you just have to pray that he'll be healed."
The Titans escaped relatively injury free, though rookie receiver Darrell Hill may have cracked a bone in his ankle on a special teams play.