Sources: Manning has stress reaction

Compensating for the plantar fasciitis he battled for much of this season, New York quarterback Eli Manning has developed a stress reaction in his right foot that could be even more problematic for the Giants, according to sources close to the situation.

A recent MRI on Manning's foot revealed the stress reaction in the cuboid bone, which makes Manning susceptible to a stress fracture that could end his 2009 season.

Before any stress fracture develops, the Giants are aggressively treating the stress reaction, trying to get Manning to stay off it as much as possible, having him wear extra supportive shoes and using a bone stimulator on the injured area.

For now, the stress reaction is not enough to sideline Manning. But Manning has been spotted favoring the foot, which he was doing as recently as Thursday night, when he was seen limping at times.

After consulting with other foot specialists in recent weeks, the Giants are not surprised -- they had come to expect that the plantar fasciitis could lead to the stress reaction.

Manning was able to play Thursday night at Denver, where he completed 24-of-40 passes for 230 yards and one interception during the Giants' 26-6 loss to the Broncos.

More than anything, the stress reaction provides another glimpse as to what Manning has had to endure this season. He started the season with plantar fasciitis, later aggravated the injury, and then developed a stress reaction in his foot. It is hardly the only reason for his recent struggles, but it certainly has not helped.

The Giants believe Manning is recovered from the plantar fasciitis and it no longer is an issue.

Even with the stress reaction, the Giants have been in compliance on the NFL's injury report, continually listing Manning with a "foot" injury.

Adam Schefter is ESPN's NFL Insider.