SAN DIEGO -- A red welt was turning purple below La'el Collins' right eye after Thursday's preseason opener against the San Diego Chargers. He had another cut just above the bridge of his nose.

"Hey, man, that comes with the game," Collins said. "I love it."

Collins' debut with the Dallas Cowboys was a success. He didn't start -- the left guard spot remains in Ronald Leary's control -- but he played three quarters and had moments that showed why teams had him labeled as a first-round talent.

On Gus Johnson's touchdown run, Collins moved from a combination block to an oncoming linebacker at the last moment to give the runner just enough room to burrow his way into the end zone.

"I just got a really good fit on the three-technique and soon as the linebacker broke the heels of the defensive linemen, I launched off and picked up a great block," Collins said. "The back did a great job of being patient and he got up there right in the middle."

He also pancaked a Chargers defender so far down field on one play that he celebrated.

"Hey, man, it's fun," Collins said. "I really love this game. For me, that is my touchdown."

Collins figures that's where he got the black eye because his helmet came down on top of his head. He first thought he had some grass in his eye.

That he was playing at all was what mattered most to Collins. His dream was nearly derailed in the spring when he was questioned in a murder case. Instead of going in the first round, he was not drafted at all. The Cowboys signed him to a fully guaranteed three-year contract as an undrafted free agent but offered no promises of a starting job.

"You live every day to make that dream come true," Collins said, "and just to be out there is a dream come true to get an opportunity to be out there."

The only snaps Collins has received with the first team came when Leary was out for a day with back spasms. The competition many suspected would happen has not quite happened yet.

"Honestly, I just see myself so far behind that those guys are so advanced at what they do," Collins said. "For me, I come in every day with a pen and pad and write down everything that I can to help better my game. And then we just go out there every day and grind."