"You have to perform. If you don't, they'll find somebody else."
Colvin is gone. But his No. 59 was given to Odom, also a Purdue product and linebacker, for the time being. Colvin, who signed with the Patriots in the offseason, was the Bears' top sack producer the past two seasons. The team isn't expecting miracles from a rookie like Odom to take his place, but they'd like to see the sixth-round pick develop into another Colvin over the years.
Colvin led the Bears with 10 1/2 sacks in each of the previous two seasons. His replacement is Bryan Knight, a fifth-round pick a year ago, but it could turn into a committee position where numerous guys pitch in and see action.
"I'd be a liar if I said we wouldn't miss Rosey Colvin," Bears coach Dick Jauron said. "He played well for us and he made a lot of plays."
Odom, who played both inside and outside linebacker at Purdue, moved into the starting lineup late his freshman year and started 34 of 46 games overall.
"When you're in college, you're pretty much guaranteed of sticking around, even if you slack," Odom said. "But here, you have the slightest room for error. They know you're new, but that's not going to get you any breaks.
"You can't make mistakes, because they'll lose faith in you."
Odom is one of those bubble guys, a player who will need to turn some heads on special teams if he's going to make the squad. One thing hurting him is the depth at linebacker. The position is probably the most talented and led by superstar Brian Urlacher. Throw in Warrick Holdman, Knight and Bobbie Howard, along with veteran Mike Caldwell and third-round pick Lance Briggs, and it's a logjam at the position.
"What we tell the young players is, this isn't college," Jauron said. "We can't wait for their junior year; we can't redshirt them. They have to show up fast."
Right now, Odom's best shot might be the practice squad, where he can learn and hopefully develop into a player. Colvin turned out to be a steal in the fourth- round, and the Bears can only hope the same thing can eventually be said about Odom.
Odom, who had seven sacks, four interceptions and blocked two kicks during his career at Purdue, made an impact at practice Wednesday when he intercepted a Chris Chandler pass in the end zone during a goal-line series. He got some high-fives from teammates and some cheers from the crowd.
"Big plays is what the NFL is all about," Odom said. "They want guys who can make the turnovers, because that's one of the biggest aspects of the NFL.
"The teams with the biggest turnover ratio are the ones usually on top and playing in Super Bowls. If you get a chance to make a play, you better make it."