New York Giants quarterback Eli Manning did not finish practice Wednesday morning due to a "stomach bug," Giants coach Tom Coughlin told reporters.Coughlin added that he hoped his quarterback's illness was a "24-hour deal."No doubt the Giants hope so as well, what with Manning playing of late like the self-described "elite" quarterback he proclaimed himself to be earlier this season and after taking a look at the Giants' depth chart. David Carr, the former No. 1 overall draft pick out of Fresno State and one-time 49ers quarterback, is Manning's backup.Carr, who did not take a single snap this season, last played in an NFL game on Oct. 24, 2010 ... for the 49ers. It was his only appearance for the 49ers, in relief of an injured Alex Smith, and Carr completed five of 13 passes for 67 yards and an interception for a ghastly passer rating of 23.6 in a 23-20 loss at Carolina. Carr had his contract terminated by the 49ers almost as soon as the lockout ended, on July 29."A lot of people had to leave, me included," Carr said this week, according to Giants.com. "But it ended up working out for me and hopefully for a lot of the guys that had to leave. It would have been nice to get a chance to stay out there, but this worked out pretty well too."Carr, who was drafted by Houston in 2002, has also spent time with Carolina and had an earlier stint with the Giants. The way things ended in San Francisco, though, left a particularly bitter taste in the California native's mouth.He spoke of it in training camp."I kind of knew from the spring that it wasn't going to be a situation where I was going to get to compete for anything," Carr said in August. "That was kind of frustrating for me all the way back then. This was last spring. This was before the season. As far as how they were giving the reps out and what not. That was the tough part for me. I kind of wanted to come back to New York then."What happened was when the general manager (Scott McLoughan) that was there brought me in, the understanding was that I was going to compete. Then he ended up getting fired and they brought in a new general manager (Trent Baalke). They have their own ideas. I kind of just got washed up to the side."I was like, man, this is not going to be good."Carr said he also spoke to incoming 49ers coach Jim Harbaugh about his prospects."I think he was straight up with me," Carr said. "He said that anybody that's in camp is going to get the chance to compete for the job. I just happened to not be in camp."And the Giants hope Carr is not in the NFC title game come Sunday at Candlestick Park..