Tahir Whitehead will fill Stephen Tulloch's role as the Lions' middle linebacker moving forward this year.
In his third NFL season, Whitehead earned the starting strong-side linebacker position out of training camp, but with Tulloch suffering a torn anterior cruciate ligament in Sunday's 19-7 win over the Green Bay Packers, Whitehead will move inside.
DeAndre Levy will remain the weak-side linebacker, a position in which he's especially excelled last year and at the beginning of 2014.
"Typically, if a guy's playing really, really well, you don't necessarily want to move that guy, and you want to maybe allow someone else to take the other position," Lions coach Jim Caldwell said. "Levy's been playing extremely well at his normal spot, so if we didn't have to disrupt it too much, we didn't plan to do so."
However, Caldwell said both Whitehead and Levy are versatile, so there's a chance the Lions move them around to confuse offenses.
After Tulloch left in the first quarter Sunday, Levy handled the defensive calls, but Whitehead is comfortable doing that, too, if the coaches ask him. As of Wednesday, though, Whitehead wasn't sure whether he or Levy would have the speaker in his helmet.
"I've had to handle calls since OTAs," Whithead said Monday. "Whenever you're playing the Mike position, you're the one getting the calls, getting everyone lined up and you're kind of running the defense. I didn't have to do it in a regular-season game, but I had to do it in quite a few preseason games."
Even with the position switch, Caldwell said the Lions plan to continue using him regularly on special teams, though that could change.
Ashlee Palmer will become the starting strong-side linebacker, and there's a good chance he'll play a significant role this week against the New York Jets, who rank second in the NFL in rushing.
The Lions, though, have played the majority of the season in the nickel, and so when that's the case, Whitehead and Levy will have to make sure they're on the same page.
"We worked well together last week when Tully went down," Whitehead said. "We're going to lean on each other to get it done."
Behind Whitehead, the Lions list Travis Lewis as the backup in the middle, but he missed Week 3 with a quad injury. Julian Stanford is listed as Levy's backup. Josh Bynes, whom the Lions signed Tuesday off the Ravens' practice squad, is behind Palmer. All of the backups can play special teams, and if the Lions suffer another injury, there's no guarantee they'll stick to the depth chart.
Through three games, the Lions defense is No. 1 in the NFL, allowing 244.3 yards per game, but Whitehead said victories will remain more important than statistics.
"We just focus on being the best defense we can be" he said. "We don't worry about the numbers. We just try to play hard and land where we land."