ALLEN PARK, Mich. — One important veteran returned to Lions practice,sort of. Another left indefinitely.

Injuries are piling up on teams across the NFL three weeks into training camp and Detroit hasn’t escaped.
Longtime kicker Jason Hanson, a two-time Pro Bowl selection and the team’s career leading scorer, underwent what coach Jim Schwartz called a “fairly minor” procedure to treat a nagging knee injury Tuesday morning. The coach wouldn’t say which knee was affected, offering only that the team hopes to have the 18-year veteran back on the field soon.
Hanson, one of only six men in NFL history to kick more than 400 field goals, made both attempts in Saturday’s preseason-opening win over Atlanta, including a 47-yarder that won the game as time expired.
The news was somewhat better for Calvin Johnson, who took the field without a cast covering his right thumb. The team’s leading returning receiver ran in some drills, but quarterbacks were instructed not to throw to him.
He missed the preseason opener and his status for Saturday’s second exhibition game at Cleveland remains unsettled.
Another player who missed the opener, rookie safety Louis Delmas, was back on the field Tuesday after being out for several full sessions with a knee injury. Schwartz said a cautious approach to his return proved to be the correct one.
“He’s feeling better. He’s moving well,” Schwartz said of the second-round pick. “He did a really, really good job of playing through his eyes rather than his feet (while he was out).
“When he does that, it’s like he never missed a day.”
Schwartz would not say if Delmas will play at Cleveland, but he all but ruled out rookie tight end Brandon Pettigrew, stymied by a quadriceps injury since the early days of camp.
“It’s been a nagging thing. It hasn’t responded as well as we’ve hoped,” Schwartz said of the injury.
Rookie kicker Swayze Waters, who opened camp with the Lions but was released last week, was re-signed Tuesday. The team cleared a roster spot by placing linebacker Cody Spencer on injured reserve. The six-year veteran tore the ACL in his right knee in Saturday’s preseason-opening win over Atlanta.
He joined offensive tackle Damion Cook (triceps) and defensive end Jared DeVries (Achilles’ tear) on the season-ending injury list.