ALLEN PARK — While most of the Lions rookies and veterans are shaking rust off from not playing since December, it’s a whole different story for Caleb Campbell.

The rookie first lieutenant, who was drafted by the Lions in 2008, played at Army and then served two years of active duty (which did not include football) before showing up for rookie minicamp a couple weeks ago.

Still, as he showed on the field at Thursday’s OTAs, he is holding his own despite the fact he’s learning how to play linebacker after playing safety in college.

“He’s made drastic improvement really from Tuesday in a lot of his things and the rookie camp we had,’’ coach Jim Schwartz said Thursday. “He’s shaking some rust off just as a football player, but you’re adding a position change to that. I think he’s done a great job so far.’’

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