Johnson, the No. 2 pick in April's draft out of Georgia Tech, was injured during Detroit's 56-21 loss to the Philadelphia Eagles when he landed hard on his back while catching a pass.
Lions coach Rod Marinelli said tests only showed bad bruising, and Johnson was moving very gingerly at the team's practice facility on Monday. Marinelli said he considers Johnson "day to day".
Johnson has 10 catches for 189 yards and two touchdowns in three games.
RAMS: Running back Steven Jackson will miss at least one week with a partial tear of his left groin, an injury sustained in the fourth quarter of Sunday's 24-3 loss at Tampa Bay.
Rookie Brian Leonard, a second-round pick from Rutgers, will get his first start Sunday at Dallas. Coach Scott Linehan said Jackson would be week-to-week.
The 0-3 Rams learned they lost Jackson a day after guard Mark Setterstrom was lost for the season with a torn left knee ligament and cartilage damage.
TEXANS: Defensive tackle Cedric Killings was able to stand in the hospital on Monday and doctors are confident he'll soon be walking.
Killings' progress came one day after he left the field on a stretcher after a headfirst collision with Indianapolis receiver Roy Hall.
Killings fractured his C-4 vertebra and was unable to move any of his limbs for a time on the field on Sunday, Dr. Rob Parrish, a neurosurgeon working with Killings, said.
PANTHERS: A MRI determined quarterback Jake Delhomme won't need surgery on his strained right elbow. But Delhomme was unsure if he or backup David Carr will start Sunday against Tampa Bay.
"I'll be getting a ton of treatment on it and we'll go from there," Delhomme said.
STEELERS: Former Georgia wide receiver Hines Ward said an MRI exam on his bruised knee revealed no damage.
Ward was injured in the third quarter of a 37-16 victory over San Francisco on Sunday when he took a helmet to the knee, although he walked without a limp while reporting to a team meeting Monday.
EAGLES: Brian Westbrook has an abdominal strain and his availability for practice and Sunday's game against the New York Giants will be determined later this week.