Julius Jones suffered a bruised chest, coach Jim Mora said, and not a broken rib as he initially thought after the game.
Mora clarified the injury during his radio show on KIRO-FM Monday morning.
The bruised chest caused bleeding into Jones' lungs, and he remained in Arizona last night at the hospital after the team left.
"It wasn't a rib. It's a bruise causing bleeding in his lungs," Mora said, according to a summary on the team's official Web site. "It doesn't appear to be anything real serious. It's serious obviously or he wouldn't be in a hospital, but it's something he'll recover from quickly.
"We're certainly thinking of him and wishing him the best. It's tough when you have to leave a guy behind in the hospital. That weighs on everyone's minds."