"He has made mistakes and he knows that," said Denver coach Mike Shanahan, who drafted troubled Ohio State running back Maurice Clarett in the third round in 2005. That move didn't work out as Clarett was cut in training camp.
The Broncos made it clear there will be no second chances for Thomas.
"You talk about taking an educated gamble," Shanahan said. "If they do make a mistake, then you have to release a player and let them go. No one's bigger than the team. We've had players before that have been in this situation, and it's been the best thing that's ever happened. They come into the NFL without a second chance.
"Time will tell. I can't tell you 100 percent. If I didn't have a very good gut feeling about the guy he wouldn't be with our organization."
The Broncos moved up four spots in the first round Saturday to select Florida defensive end Jarvis Moss with the 17th pick. Moss tested positive for marijuana in the middle of the 2006 season and was suspended for one game.
"I addressed it like a man," Moss said. "My mistake. I stepped out of line."
Moss said he couldn't believe Thomas would be joining him in Denver.
"Marcus was hands down the best football player on our national championship team," Moss said. "He's definitely a top-10 player. He's a special player."
* Heisman Trophy winner Troy Smith was selected by Baltimore with the final pick in the fifth round, the 174th overall.
* The New York Giants selected Brown linebacker Zac DeOssie, from Brown, in the fourth round.
DeOssie's father, Steve, was a linebacker who played for the Giants from 1989-93, winning the Super Bowl in 1990.
The DeOssies were together when the Giants made the pick.
"I broke down right when it happened," Zac DeOssie said. "My old man was right next to me. Football is a big part of my life and a big part of my family's life and I could not see a better fit for myself." *