Culpepper practiced Wednesday, a day after signing with the winless Lions and a couple months after announcing his retirement.
"I'm like a sponge right now, trying to absorb it all," he said.
Culpepper split snaps with the first-string offense with second-year pro Drew Stanton.
"It was pretty even," wide receiver Shaun McDonald said when asked how the repetitions were divided. "Daunte might've had a little bit more."
Dan Orlovsky, meanwhile, watched practice with a soft cast protecting his injured right hand after starting the past four games.
Orlovsky said he had "no idea" whether he could be ready to play this week and Stanton said he hopes to get a chance to play in an NFL game for the first time.
Lions coach Rod Marinelli was noncommittal about his plans to split snaps during practice or for Sunday's game at home against Jacksonville.
The 31-year-old Culpepper signed Tuesday with the Lions, ending his brief retirement. He started 11 lackluster games the previous two seasons for Oakland and Miami. He was a star in Minnesota before a knee injury stunted his career in 2005.
"I definitely feel that I can go out there and be myself," he said. "I'm 100 percent healthy and I feel great."