When Addison arrived at Bears training camp in 2011, it represented a personal triumph for the undrafted rookie given the obstacles he overcame to get there.

Addison didn't see it that way. Rather than a personal triumph, he took it personal.

"I got calls all the way through the draft. 'Be ready, Mario. We're going to draft you,' " Addison recalled. "But then we get to the seventh round, and I still hadn't been drafted.

"Nobody drafted me, and I got discouraged. Some guys I had played against were already in the league, and I had competed with those guys and I did well against them. I did all this work just to make it to the NFL, and I knew I had the talent to play."

Addison soon felt wanted again, when nearly half the league showed interest in bringing him to training camp, but he never has forgotten how he felt immediately after the draft.

"I always said that if the good Lord blesses me with the chance to even step onto an NFL field, I'm going to give it my all," Addison said. "With the way I grew up, I've still got some of that fire."

Addison got calls from interested teams right after the draft, but he and the league's other rookies had to fly solo for months. The draft itself provided a brief reprieve from the owners' decision to lock the players out while the sides negotiated a new Collective Bargaining Agreement. The Panthers' draftees that year, led by No. 1 overall selection Cam Newton, had a few hours at Bank of America Stadium right after the draft before they had to head back out, not to be seen again until training camp three months later.

Addison didn't even get that luxury with the Bears. When he arrived at Olivet Nazerene University in Bourbonnais, Illinois (incidentally as tight end Greg Olsen was being traded by the Bears to the Panthers), Addison didn't feel like the big man on campus for any number of reasons.

"That was one of the toughest times of my life," Addison said. "They shut everybody out. I had to wait until the lockout was over until I could sign with Chicago, and then I'm in Chicago two days later. I just packed a bag and went.

"OTAs are for building relationships with your team, learning the playbook and things like that, but I didn't have any of that because of the lockout. I went straight into training camp. I was nervous, didn't know what to expect. Just walking around, it was like, 'Man, that guy is big.' You're sizing everybody up. I'd see a guy my size and think, 'He's probably a D-end.' Then I'd find out that, man, he's a receiver!"

And come the first practice, Addison didn't exactly feel welcomed by the veterans.

"The defensive line had a lot of vets, and you really had to prove yourself to those guys before they'd even really hold a conversation with you," Addison said. "We'd come out of the locker room at the same time and I'd try to talk to them, and they'd look at me sideways and keep walking. You've got to be a real man to even handle that."

Peppers doesn't remember giving Addison any sort of cold shoulder, saying he's always treated rookies as teammates. Perhaps Peppers' soft-spoken nature could have been mistaken for the silent treatment, but the point was moot after just a few days when Addison's competitive spirit proved impossible to ignore.

"Probably like the third day, I came out there blazing, getting some first-team tackles, killing the tight end. I was outworking them, spin-moving them," Addison recalled. "Pep was like, 'You've got a chance. You've just got to keep working hard.'

"I earned their respect at camp."

Addison still had to beat out many of those same players and had to win over the coaches if he hoped to stick around. In what Addison called the hottest summer of his life, his feet were put to the fire in more ways than one.