Petitgout was hurt blocking Alex Brown on a pass play. The Giants did not say Monday how long Petitgout would be out.
"It's not weight-bearing," Petitgout said after the game. "Guys have played with it before. I just have to get some more tests and see if there is anything else wrong. No one has said how long I'm going to be out."
New York also lost starting cornerback Sam Madison, who injured his right hamstring trying to cover Mark Bradley on a touchdown catch late in the first half. Madison had missed the two previous games with a hamstring injury.
Tiki Barber, the NFL's leading rusher, injured his right hand in the first quarter. He returned on the next series and finished with 141 yards on 19 carries. Afterward, Barber received X-rays on his injured right hand -- the Giants are calling the injury a sprain -- but they were inconclusive. He will be re-examined Monday.
Barber, whose hand was wrapped in ice, told ESPN's Rachel Nichols that he is "not expecting it to be a big deal." When asked if he thought he would miss time, Barber said "I never miss time, but I guess we'll see."
He joins a growing list of injured Giants starters.
Pro Bowl defensive ends Michael Strahan (foot) and Osi Umenyiora
(hip) also were inactive. The Giants also were without receiver Amani Toomer, who was placed in injured reserve this past week with a knee injury.
Emmons (groin) and Short (quad) were both questionable all week. Reggie Torbor got the start for Emmons, who was hurt last week, while rookie Gerris Wilkinson got his second straight start in place of Short.
The Giants made an interesting move to replace Strahan, who'll be sidelined for at least two weeks with a sprained foot. Four-year veteran William Joseph, who normally is a backup tackle, was moved to end and given the start ahead of Adrian Awasom, the recently signed practice squad player who filled in last week after Strahan was hurt against Houston.
All-Pro middle linebacker Brian Urlacher was in the starting lineup after missing most of practice this past week with a toe injury.
Information from The Associated Press was used in this report.