Manning, who has started in the Giants' last 82 games, was held out of practice Wednesday so he could receive treatment on his plantar fascia, a band of connective tissue that runs along the bottom of the foot and inserts into the heel.
"If I feel like I can go out and play at a high level and help the team and do everything I can do, and they don't have to limit the game plan or say you can't do this or that, I'll go out there and play," Manning said. "I'm not going to do anything that will put myself in harm for making this worse down the road."
Manning admitted that his heel occasionally bothered him the last few weeks. However, he never had pain like he felt in the fourth quarter of last Sunday's game when he set up to throw a pass against the Kansas City Chiefs and literally had to hop because it so was intense.
"It never bothered me at practice," said Manning, who has led the Giants to a 4-0 start. "It never kept me from doing anything."
Manning had the most basic treatment Wednesday: electric stimulation and ice. He also was fitted for an orthotic for his shoe. He watched videotapes of the Raiders' defense, went over this week's game plan, planned to watch tape of practice, discuss it with his receivers and then go over his notes.
But Manning's biggest concern was his heel, which he said is improving. Manning said he felt less pain than on Monday and Tuesday and that he was moving around better. He said he was in no pain while talking in front of his locker.
Manning has asked the Giants' medical staff whether playing this weekend might make his injury worse. They told him they just don't know.
"As an athlete, you know when something is bothering you and when something is going to get worse or not, and I'll make that decision," Manning said.
Wait and see is the way Manning described his plans for both practice the rest of this week and the game.
"I feel like I have been practicing well and playing good football and been in a rhythm the last couple of weeks," Manning said. "You don't want to go out there when you are injured and you can't do everything you want to do and move the way you want, and all the sudden you get bad habits and bad mechanics and you're throwing the ball differently."
Manning said he would like to practice some time this week, but he noted he could play without practicing.
When Manning hurt the A-C joint in his right shoulder early in the 2007 season, he missed practice on Wednesday and Thursday and took only half the snaps on Friday before starting against the Green Bay Packers.
"I was probably more worried about my shoulder than this," Manning said. "It was my throwing shoulder, and I couldn't even throw when I hurt that. I couldn't throw the ball 10 yards. I know I can throw the ball now, it's the moving around and all the other things I have to take care of."
"He will know everything," Coughlin said. "While he is in here today, he will have a (video) machine in front of him. His tape time will probably be as good as or maybe more than a normal week. Yeah, he will study hard."
Veteran David Carr, the No. 1 overall pick by the Houston Texans in the 2002 NFL Draft, would replace Manning if he cannot play. Carr has 79 career starts, but none since 2006 with the Carolina Panthers.
"The game plan is not going to be adjusted," Coughlin said. "He has been a starter in this league. He has been very much into what we have done from the standpoint of a plan each week. We wouldn't taper a whole lot."
Notes: TE Kevin Boss didn't practice because of a sprained right ankle. He said it's improving. ... Chase Blackburn will start at weakside linebacker with Michael Boley expected to be sidelined for one month following surgery on his right knee. ... HB Danny Ware practiced for the first time since dislocating his left elbow on the opening kickoff in the first game of the season.
Copyright 2009 by The Associated Press