Idonije is one of several reserves expected to see more playing time against the Vikings. He's been part of the defensive line rotation all season, but this will be his first chance to play down in and down out.
The key will be to do more than just replace a starter.
"I've got to go in there and not just be on the field, I've got to make things happen," Idonije said. "I've got to make an impact."
Catching the coaches' eye has been tough for several second team players since they haven't gotten many reps in practice since training camp.
"It's hard to get reps in practice when you're not a starter," said CB Rashied Davis. "I mostly run scout team so to be able to go out there and actually run the defense and to prepare for possibly the future that'll be great."
Davis could also see additional time at kick returner. He handled the role last week at Green Bay, as Jerry Azumah's hip has acted up down the stretch. He could be the top choice to take the responsibility in the postseason, which means every chance to practice in a game is valuable.
"The more reps the better you get at something," Davis said. "The more I'm out there the better I'll get at making reads and feeling out where the blockers are supposed to be."
The Bears only have four receivers on the roster and Eddie Berlin has played just one snap at the position since re-signing with the team on Nov. 25.
Despite being a five-year veteran in the league, the trip to Minnesota is a chance for him to shake off the rust incase he's needed.
"Justin (Gage), Bernard (Berrian) and Moose (Muhsin Muhammad) are all playing really well right now, but in a playoff game or any game you never know if a guy goes down," Berlin said. "So it would be good if I'm needed in a playoff game you've got a little experience and having snaps in a game so I think it's going to benefit quite a few guys this game."
Thomas Jones would like to cap his best season by going over the 1,300-yard mark. He would be just the second running back in franchise history to accomplish the feat.
However, as soon as Jones gets the necessary yardage he will take the rest of the day off. With Cedric Benson still having doubts about his sprained MCL, Adrian Peterson is likely to get the bulk of the carries on the day.
Peterson is a sure bet to get his third double-digit carry game of the season and could reach the 20-attempt plateau for just the second time in his career.
"That would be great," Peterson said. "If I get 7 carries I'll make the best of it, if I get 20 I'm still going to try to do the same thing."
To win the Super Bowl the Bears have to play three playoff games. The important thing is to walk away from the season finale with the starters intact and the backups prepared incase they're needed in the postseason.
"Some guys, like me, haven't played a ton of snaps on offense or defense and could be called upon in the playoffs. There's no going home at that point so you've got to be ready," Berlin said. "There's no substitute for getting game experience in that situation."
Berlin and the rest of reserves will get ample opportunity to simulate the situation on Sunday.