In 2007, the NFL instituted a rule that states a player who loses consciousness during the course of a game cannot return to that game.
Westbrook didn't practice Wednesday, nor did he do his scheduled weekly press conference.
Reid and Eagles trainer Rick Burkholder both said the star running back was doing better immediately after the game.
"His eyes were clear," Reid said. "He didn't have that hazy look about him."
Burkholder, who ushered Westbrook off the field, is taking the one-day-at-a-time approach, but he's encouraged by what he has seen.
"He knows everything," Burkholder said. "He knows his brother was on the field. He knows Andy was behind me. He remembers walking off the field, going to the locker room, being on the field in the second half. He remembers all of that.
"Now we're looking at a headache. Once his headache clears, and it's a mild headache, but it's still a headache. Once that clears, we'll get his heart rate up and see how he responds. If he does well there, we'll try some football drills."
The Eagles have one less day to get Westbrook back after playing Monday night.
"That's one of the things I told management after the game," Burkholder said. "We have a short week. That will play into it. But I can't worry about that. I worry about Brian."
If Westbrook can't play, he will be replaced by rookie running back LeSean McCoy, the team's second-round draft pick out of Pitt.
McCoy played in place of Westbrook, who was out with a knee injury against the Kansas City Chiefs in the third game of the season, and finished with 84 yards on 20 carries with one touchdown.
Westbrook has done well against the Giants. In nine games against New York, he has topped 100 total yards eight times and 100 rushing yards five times. He also has scored 11 touchdowns in those nine games.
This week, he might not.
McCoy, for his part, said he's ready if he has to go.
"There's always a little pressure on you," he said. "But that's my job to go in and help us out, if Brian can't go."
Looking to bolster their depth at the position, the Eagles signed P.J. Hill off the New Orleans Saints' practice squad. The Saints signed Hill as a rookie free agent out of Wisconsin, and he carried 26 times for 128 yards and scored three touchdowns during the preseason. Among the Saints' final cuts, Hill was signed to the team's practice squad on Sept. 7.
Notes: To make room for Hill, the Eagles put LB Omar Gaither (foot) on season-ending injured reserve. ... Reid ruled DE Victor Abiamiri (knee) and WR Kevin Curtis (knee) out for Sunday's game. ... DE Darren Howard (ankle), WR DeSean Jackson (foot) and S Victor Harris (ankle) didn't practice Wednesday, but they are expected to be ready by Sunday.
Copyright 2009 by The Associated Press