Doctors believe Bradley could be back in four weeks, and the Eagles plan to keep his roster spot available.
Chaney has impressed the Philadelphia coaching staff in limited duty. He was credited with seven tackles in the win over Dallas.
"You could tell he had done his homework when he stepped in for Bradley," Reid said. "He didn't miss a beat as far as the calls go. He gets better every time he has an opportunity to play. You saw that during camp, so I would expect that, when he has this opportunity to play."
"They'll test the linebackers," Reid said, "with that run game and the way the tight end plays, and the screen game and so on."
Consider the rookie warned.
"I've just got to do my thing," Chaney said, "and be ready for whatever they throw at me."
The Giants average 148.3 yards per game on the ground, good for fourth in the NFL, and have been particularly effective lately. They rushed 36 times for 197 yards in a 31-7 victory over the Washington Redskins on Dec. 5, and added a season-high 213 yards on 28 carries in Monday night's 21-3 victory over the Minnesota Vikings.
Brandon Jacobs, a punishing inside runner, rushed 14 times for 116 yards and a touchdown against the Vikings, and Ahmad Bradshaw, a breakaway threat, added 103 yards and a score on 11 carries. It was the first time since 2007 that both players exceeded the 100-yard mark in the same game.
Against the Redskins, Jacobs ran eight times for 103 yards, and Bradshaw added 25 carries for 97 yards. Each ran for two scores.
An impressive run, to say the least.
"They got the big fella (Jacobs) more involved," Reid said. "And they let Bradshaw be kind of the rotation guy there. And that seems to have worked."
It has been quite different for New York's tailbacks ever since.
"We've pounded away," Coughlin said. "We've just stayed persistent and made some plays."
Chaney was a two-time All-SEC performer at Mississippi State, and on his pro scouting day, he tested out as the fastest linebacker eligible for the draft. He clocked a blazing 4.54 seconds in the 40-yard dash, but he still slipped to the final round, when the Eagles made him the 220th overall selection. He was the 24th linebacker taken.
"I was disappointed," Chaney said, "but at the same time, I came in with a chip on my shoulder, wanting to prove everybody wrong. This is a good opportunity to do that, too. A lot of GMs passed on me, so I want to make it known that they made a mistake."
Reid said the Eagles were impressed not only with Chaney's physical tools, but the fact that he played the middle in college, and was asked to make the defensive calls, as he is doing now.
"The funniest thing was the first time he came in the huddle (in the Dallas game), I was expecting him to be wide-eyed and be kind of quiet, and he really wasn't," safety Quintin Mikell said. "He stepped up. He barked out the call. He was loud, assertive. I think that's when I knew, 'OK, he's going to do his thing.' Because he wasn't scared."
That will only be half the battle Sunday, though.
"Listen, you're playing a very physical offense," Reid said. "There's a physical challenge for all of them. The mental part of it, as long as he's continuing to prep like he did, getting to the spot, he should be OK. In other words, he's built a foundation there that he can go back and draw off of, to help him through this now, where he's the starter."
Notes:Eagles CB Asante Samuel, who missed the last three games with a knee injury, practiced Wednesday. But his status is uncertain. "To be determined," said Samuel, who leads the NFL with seven interceptions. "I need to get some more picks, man ... some more turnovers," Samuel said. "I've been stuck on seven for three weeks now. My goal is to win Defensive Player of the Year this year."
The Associated Press contributed to this report.