The one spot to fill - vacated by Justin Durant when he signed with the Cowboys - is at outside linebacker.
Tulloch told reporters Thursday that even he's eager to see how it all plays out.
"I'm excited about it," he said. "Just these last couple days, to see the state of mind of those players. Travis Lewis is probably one of the first guys here (in the morning for training program).
"I'm working with Ashlee Palmer. Tahir Whitehead is working by himself in the weight room, focused. Whenever you can build a competition between young players like that, it sets up good things to come."
Palmer, who's entering his fifth season in the league, emerged as a force on special teams last year and even started two games due to a Levy injury.
If the Lions were playing a game tomorrow, Palmer would likely get the nod.
The Lions moved up in the fifth round last year to draft Whitehead -- giving up a fourth-round pick this year in the process. He played in 14 games last year – all on special teams – and finished with 11 tackles and a forced fumble.
Lewis, a seventh-round pick last April, played almost exclusively on special teams last season (three snaps on defense) and had three tackles.
Tulloch was asked to handicap each player's strength heading into the competition.
On Palmer: "Obviously, Ashlee Palmer has been in the league a long time. He's coming around as a player. When I first got here, he was kind of just trying to feel his way through. Now, he's one of the top leaders on special teams, and he had a chance to start a couple games last year and showed up."
On Lewis: "Raw, but talented. He can run like a deer. All-time leading tackler at Oklahoma. A very instinctive (player)."
On Whitehead: "When he first came in he was raw. He was more of an outside rush end/linebacker. He moved to a 4-3 position, but has great ability to move his hips. Good instincts and very strong at the point of attack."
"All three of those guys bring different things to their game and it's going to be interesting to see who wins this battle," Tulloch said. "It's going to be real interesting to see how that pans out, but I know whoever wins that job will definitely hold it down."