Manning's teammates say he's a competitor who will play if he's able. Carr wants to be out there just as much, and his chances of playing this weekend seemingly improved Thursday when Manning missed his second consecutive practice with an injured right heel.
After practice, Giants coach Tom Coughlin declined to predict whether Manning would be able to start his 83rd consecutive game, saying only that the inflammation in the quarterback's heel was feeling better.
A decision on whether Manning will play might not be made until Sunday.
The No. 1 overall draft pick by the Houston Texans in 2002, Carr isn't worried. He told himself that he would be the Giants' starter after Manning was hurt last Sunday during a victory over the Kansas City Chiefs and the worst that can happen is he doesn't.
"You have to prepare yourself one way or you are going to be riding a roller-coaster all week," said Carr, who last started an NFL game in 2007 for the Carolina Panthers. He was 10 of 22 for 95 yards with two interceptions in a loss to the New Orleans Saints.
Carr came to the Giants as Manning's backup last season and mostly has been an understudy. He appeared in just three games last season and two this year, all off the bench.
"I am sure he wants to play really bad, probably as bad as I want to play," Carr said of Manning. "It's the same for every competitor, every guy who wants to be on the field. Everybody gets hurt. We're down a lot of guys now, and I think everyone on the side wants to be out there to help the team."
Giants offensive coordinator Kevin Gilbride has no doubts about Carr. He said the eight-year veteran knows the offense, but he might not be as familiar with some of its subtleties as Manning, who has been the Giants' starting quarterback since midway through the 2004 season.
"I expect him to do well," Gilbride said of Carr. "I would be disappointed if he doesn't play well."
Gilbride said the biggest difference is that he and Manning are on the same page after working together the past six years. Gilbride said he can look at Manning and the quarterback can almost immediately sense what is wrong and go back on the field and act like a coach in the huddle, conveying the coordinator's concerns to the offense.
"It's got to be frustrating for a guy that started to just be on the sidelines, and now he has a chance," Gilbride said. "So I think if I was him, and what I have observed looking at him, he seems genuinely excited about this opportunity."
For the first two days of practice, Carr has received the chance to throw to Steve Smith and Mario Manningham, hand off to Brandon Jacobs and play behind a first-team offensive line that has started 36 consecutive games.
"It's nice to play with the toys," Carr said. "Sometimes you feel like the brother who doesn't get to play with all he cool stuff."
Carr admits he has come a long way since his rookie season with the Texans, when he was sacked an NFL-record 76 times.
"It's not even close for me mentally," Carr said. "I feel like a totally different quarterback as far as what to expect, my preparations, how I go about the game is a whole lot different than then. I guess it's what you learn going through the things I have gone through, except I'm a better player."
Carr also has a solid offensive line, so there is no need to duck and cover after every pass.
"If my number is called, I will go out there and have lot of fun," Carr said. "We have a lot of great players on this team. We are on a win streak. Guys are feeling good, and I want to be a part of it. It was good to get out there and throw some ball with those guys and sweat. It kind of felt like the old days."
Copyright 2009 by The Associated Press