Madison, who was ineffective at times last season because of a hamstring problem, pulled the muscle in his left leg. His status of the season opener at Dallas on Sept. 9 is uncertain, coach Tom Coughlin said in a conference call on Monday.
The coach had no news on seven-time Pro Bowl defensive end Michael Strahan, whose holdout is now in its fourth week while he decides whether to retire or return for a 15th season.
Tony Agnone, Strahan's agent, expects his client to reach a decision soon.
The most serious is a torn Achilles' tendon sustained by backup receiver Michael Jennings, who will need surgery. The second-year pro will miss the rest of the season.
Safety Will Demps, who is fighting James Butler for a starting job, will be out two-to-three weeks with a dislocated right elbow. Backup center Grey Ruegamer will miss the rest of the preseason with a high sprain to the right ankle.
Receiver Steve Smith, the second-round draft pick, and defensive tackle Jonas Seawright, both sustained concussions. Smith, who caught a touchdown pass in the game, was feeling much better on Monday, Coughlin said.
Pro Bowl tight end Jeremy Shockey also experienced tightness in his hamstring. Coughlin hopes he will be able to practice this week.
Madison's injury is the one causing concern. He missed four games with a similar injury last season.
Coughlin said the normal timeframe for a hamstring is a couple of weeks. However, Madison's struggles last season with the injury might convince team doctors to hold him out a little longer.
"Speculating is a difficult thing because you are not aware of how this is going to be in two weeks," Coughlin said. "Maybe he is ready to go, I don't know. He has dealt with these things before."
"It has just been one of those days," said Coughlin, who was upset about Jennings' injury because the young receiver had worked very hard.
Coughlin was very pleased with the improvement of the defense, which allowed a touchdown and several big runs in its only series against the Carolina Panthers a week ago.
Baltimore got four field goals in the game, including one that followed an early fumble by quarterback Eli Manning that was recovered at the New York 12.
"The fact that we weren't satisfied and we went out and did something about it is a good thing," Coughlin said.
"Guys came out with a different mind-set and I think it showed," he said.
Coughlin was also impressed with free agent kicker Josh Huston, who made field goals from 30 and 50 yards. He also had good hang time on his kickoffs, which puts him in the running for the No. 1 job with veteran Lawrence Tynes.
"He definitely helped himself and it was good to see," Coughlin said of Huston. "Now, hopefully, we will get some opportunities for Lawrence as well."
Copyright 2007 by The Associated Press