Lions WR Calvin Johnson 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."