Ross immediately fell to the grass and grabbed his hamstring, the same injury that recently kept him out for a week. The third-year pro had returned to practice Monday.
"It felt like someone shot me," Ross said after the workout. "It was cramping in three different places. Hopefully, it won't take more than 18 days. The first game is in 19 days."
Ross had his leg wrapped by trainers and then walked to the sidelines where he talked to halfback Ahmad Bradshaw and linebacker Michael Boley, who has missed all of training camp while coming back from hip surgery.
Ross was eventually taken in a golf cart to the Giants locker room.
Coach Tom Coughlin did not know whether the injury was serious.
"The poor kid can't get beyond that," Coughlin said. "He was obviously working his way back and made a sudden move to try to catch back up to a receiver who was going by. It was very frustrating because he has not had a lot of time on the field."
Ross has had some mild hamstring strains and problems with cramping since being taken as a first-round pick by the Giants in 2007. The latest problem is more severe.
"You watch those two guys practice and they've certainly benefited from the amount of snaps, and they haven't backed down a bit, so I am hoping that stays that way," Coughlin said.
The coach seemed frustrated by the number of nagging injuries during camp at the University at Albany.
Defensive tackle Chris Canty, who signed a six-year, $42 million contract as a free agent, has been sidelined for weeks with a hamstring injury that Coughlin recently said is a tear. Canty was treated in New York City on Monday.
Defensive tackle Rocky Bernard, who signed a four-year, $16 million contract, missed the opening two weeks of camp with a hamstring injury he suffered while working out on his own. He is expected to play Saturday in the annual preseason game against the Jets.
The Giants reported to training camp on Aug. 2 trying to find out whether they had the receivers needed to replace Plaxico Burress and Amani Toomer. Burress was released in April, roughly four months after accidentally shooting himself in the leg. Toomer was not re-signed after spending his entire 13 years with the Giants and later signed with the Kansas City Chiefs.
In the past week, Giants first-round draft pick Hakeem Nicks has stepped up. The North Carolina product had a 55-yard catch and run late in the 17-3 loss to Chicago on Saturday night. He also had two long receptions on Monday and, after dropping two deep passes on Tuesday, he made a fingertip catch on a deep sideline pass from Manning.
"He came back with a play, which is good to see at the end," said Coughlin, who gave his team a reward by ending the last practice 30 minutes early.
The Giants are uncertain whether they will return to Albany for training camp next season or hold it at their new headquarters in East Rutherford, N.J.
"I don't know, I don't know," Mara said shortly after arriving at practice.
The team's biggest concern at Albany is not having an indoor facility for practice during inclement weather. That wasn't a problem the past 24 days; the conditioning drills on reporting day were rained out.
The Giants have an indoor practice facility at home.
"The weather has been exceptional and the idea of us being all together and being in a camp-type setting, that is very positive to us," said Coughlin, who said there are pros and cons to training at home and away.
Mara said the team hopes to make a decision on next year's camp in a few weeks.
"We're still talking," Albany Mayor Jerry Jennings said after practice. "I'm cautiously optimistic. I always am, so we are going to continue to work with them and have a decision in a couple of weeks."
The Giants will practice for the rest of the season in East Rutherford.