He isn't sure how it started. Sometime during the insufferable training-camp workouts at Lehigh, rookie middle linebacker Joe Mays picked up a nickname.

For a first-year player who hasn't yet made the team, that normally would be cause for concern. You would expect it to be something wholly unflattering - a verbal extension of the hazing rituals that neophytes endure each season.

Omar Gaither started it, Mays said.

"Someone picked up on Omar saying it, and it's stuck with me ever since," the 23-year-old said.

Head-buster. That's what some of his teammates have been calling him.

OK, so it's not exactly catchy, and you probably won't see it printed and sold on T-shirts outside Lincoln Financial Field. But as nicknames go, it's nicer than most sixth-round draft picks from a Division I-AA school could possibly hope for.

Mays, who was an all-American and his conference's defensive player of the year during his senior season at North Dakota State, quickly has earned a reputation for making big hits. In the preseason opener against Pittsburgh, Mays led the Eagles with five tackles, including one in which he upended Steelers rookie wide receiver Limas Sweed, dumping him on his head. Against Carolina on Thursday night, Mays added three tackles to his preseason statistics, though none was as vicious as the one he unloaded on Sweed.

"He's making plays," said Gaither, one of the Eagles' starting linebackers. "You see him in on a lot of plays out there, so I think his progression is going well. He certainly makes it hard for offenses when you have a guy like that who's strong and who can run and who can hit."

Of course, making plays is only part of what Mays is being asked to do to secure a job. As a middle linebacker, Mays - who was listed behind starter Stewart Bradley on the depth chart for the Panthers game - must learn defensive coordinator Jim Johnson's notoriously complicated playbook. He must know it well enough to tell his new teammates what their on-field assignments are.

"That's a big thing for the middle linebacker," linebacker Chris Gocong said. Two years ago, Gocong made the same leap from Division I-AA that Mays is attempting. The two played against each other when Gocong was at Cal Poly-San Luis Obispo. "Not only do you have to know the plays for yourself, but you have to tell everyone else what's going on."

For a guy who didn't play football until his junior year in high school, and who received only one college scholarship offer, that's no easy task. Add in that Mays is a bit undersize at 5-foot-11 and 246 pounds, and it's clear why he was considered a long shot to make the team heading into camp.

Still, Mays thinks he has a good chance to stick around if he can continue to make his teammates and the coaching staff notice him. On that front, so far, so good.

"Joe has a knack for getting to the football," coach Andy Reid said. "It's just a matter of learning the defense and having a grasp of it at the middle-linebacker position, where you're in charge of everything. He just has to continue to learn."