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Lions linebacker Stephen Tulloch, shown being watched over by Glover Quin, rests on the field after tearing his ACL against Green Bay in Week 3.

(Melanie Maxwell | MLive.com)

PHOENIX -- The Detroit Lions are in no hurry to bring back Stephen Tulloch from an ACL injury.

But whenever he does step foot on that field, he'll do so as a starter.

Coach Jim Caldwell confirmed this week that Tulloch will maintain his hold on the middle linebacker job for a fifth straight year.

"I would anticipate it," Caldwell said Wednesday during the final day of deliberations at the NFL owners meetings in Phoenix. "He's highly experienced and highly productive. And he's a great leader."

Tulloch has been one of the Lions' steadiest players since signing here as a free agent in 2011, but missed the final 14 games of last season with a torn ACL. He suffered the injury while celebrating a sack of Aaron Rodgers in a Week 3 win against the Green Bay Packers.

He's progressing well in his rehab, but it's unclear when he'll return. It seems the Lions could play it safe and hold him out of OTAs to protect his health.

"I'm less concerned about the OTAs," general manager Martin Mayhew said. "I think in his situation, being a veteran -- obviously it's a new scheme to him -- but I think we'll take our time with him. And whenever he gets back, he'll get back."

Detroit's defense was expected to take a step back without its veteran in the middle, but instead it accelerated due in part to the emergence of Tahir Whitehead at middle linebacker.

Whitehead didn't play a defensive snap in either of his first two seasons in the league, then opened the 2014 season as the starter on the strong side.

He slid into the middle after Tulloch went on injured reserve, and finished with 86 tackles -- second on the team -- and two interceptions. He was ranked the 14th-best inside linebacker according to ProFootballFocus.

The Lions lost something by replacing Tulloch with Whitehead, but not nearly as much as was expected. And because Whitehead's cap hit is about $5.1 million less than Tulloch, there was some speculation whether Tulloch could become expendable.

But that's not happening.

Caldwell said he doesn't know what Tulloch's return means for Whitehead. The fourth-year linebacker could either back up Tulloch in the middle, or try to reclaim his starting job on the strong side.

He would have to compete with Kyle Van Noy at that spot, and perhaps Josh Bynes.

"That's the great thing about it. We have some flexibility there (with Whitehead)," Caldwell said. "That's the nice thing. We can move those guys around a bit, particularly because of the fact he played so well at a number of spots we put him in. That's going to allow us to slide him where we need him to be."

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