Detroit Lions linebacker Caleb Campbell was singing the national anthem in a football uniform a couple weeks ago for the first time since he suited up Dec. 1, 2007, in the Army-Navy game.

"I got emotional," Campbell said. "I started thinking about all of my classmates protecting our country while I get to represent them in the NFL."

The West Point graduate will get another chance Saturday night in Detroit against the Cleveland Browns, playing in his third exhibition game after a long wait to resume his dream of playing professional football — a dream that prompted debate about whether it was fair for a cadet to play pro sports while his peers were at war.

Campbell, a four-year starter at strong safety for the Black Knights, was among the first Army athletes to benefit from the Alternative Service Option program, which was implemented in 2005. It allows athletes a chance to play professionally and complete their service by serving as recruiters and in the reserves.

The Air Force Academy and Naval Academy do not offer such a program. Both require two years of active service upon graduation before presenting the option of swapping the final three years of active time for six years in the reserves.

Campbell initially was told by the Army he could enter the 2008 draft, and he was taken in the seventh round by Detroit. If he made the team, he was told, he would be allowed to play in Detroit and carry out his service as a recruiter in the area.

But the Army later told Campbell, a second lieutenant, and the Lions that he would be required to serve at least two years on active duty before he could apply to be released. Campbell said he wept at the news.

"He was devastated," recalled Jordan Murray, his classmate, teammate and best friend at West Point. "He was knocking on the door of his dreams and he had to come back. Recently, though, he said it was the best thing that ever happened to him because he served his country and he's still is getting a chance to do what he's doing now with the Lions. It's incredible."

Despite two years off the field, Detroit gave him an opportunity after an impressive workout, including watching him run the 40-yard dash in about 4.5 seconds, and signed him in April.

Campbell is playing linebacker instead of safety for the first time in his life, as well as special teams. The results have been mixed.

"Like a lot of other rookies, you can make a highlight film on him that looks really good and a lowlight film that looks really bad," coach Jim Schwartz said. "He's just got to work on consistency. He's flashy. You can see his athletic ability on special teams and he's made some good plays in the open field on defense."

In his professional debut against the Pittsburgh Steelers, he was on the left side of the defense when he perfectly read a screen going the other way and made an impressive play.

"It was awesome," Campbell recalled with a grin. "My first tackle in the NFL was for a 6-yard loss and it meant something to me."

The 25-year-old Campbell, who is from Perryton, Texas, seems to mean a lot to countless U.S. soldiers stationed across the world because many of them send him messages on Facebook.

"Some guy recently told me he's going to send me the flag he used during a combat jump in Afghanistan because he wants me to put it in my locker," he said. "It gave me goose bumps, reading that note. All the things you can get in the NFL — a good paycheck and public fame — come and go, but being able to touch or inspire somebody means so much more to me.

"It would be awesome to make the team, and I truly hope I do, but my journey won't be over regardless of what happens here."

If No. 53 is on the 53-man roster in just over a week, he'll likely join a U.S. Army Reserve Unit as a lieutenant.

If not?

"I'd probably take some time off and travel, but I wouldn't mind getting back in uniform to continuing serve our country," he said. "I was a foreign-area studies major with a focus on international politics and a minor in biomedical environmental engineering, so there are a lot of things I could do."

Campbell is on the bubble to make the Lions' team just as numerous players are in Cleveland.

Browns coach Eric Mangini said the preseason game in Detroit is only one part of his evaluation process, deciding who to cut and keep.

"Really, I work off of a sheet that I've had since I've been a head coach," Mangini said. "It's kind of a worksheet based on how many you keep by position. ... It's not really just happening this week, it's something that I look at every day or every other day."