Albany, N.Y. - The interior of the New York Giants' defensive line is facing questions after veteran Shaun Rogers was lost for the season with a blood clot in his left calf and two other defensive tackles were diagnosed with back problems, including one that will require season-ending surgery.

Coach Tom Coughlin announced Tuesday that Rogers' treatment for the blood clot would prevent him from playing for the Super Bowl champions this season. His calf swelled after the Giants' preseason opener against Jacksonville, but fellow tackle Linval Joseph said Rogers also was leg whipped in practice last week.

Marvin Austin, the team's No. 2 draft pick in 2011, also was being seen by doctors in New York after his back acted up Monday night, a problem some players blamed on bad mattresses at training camp at the University at Albany.

Coughlin added free agent Marvin Parker needs surgery to repair a herniated disc that he injured the game Friday.

"I thought we were as deep (at defensive tackle) as we were at any position on the team," Coughlin said, "and it's not that way right now."

The Giants would get a boost if veteran starter Chris Canty returns. He had offseason knee surgery, though, and his rehabilitation has taken longer than expected.

Joseph, who started at tackle last season with Canty, is back, and so is veteran Rocky Bernard, who missed a couple of workouts last week with a sore knee.

First-year pro Dwayne Hendricks, who played one game last season and spent parts of three years on New York's practice squad, played well Friday, recording two sacks. Seventh-round draft pick Markus Kuhn is raw, but he is strong and has shown flashes.

Coughlin was more concerned Tuesday about Rogers, who was signed as a free agent. He lost 50 pounds before reporting to camp and he was expected to add size to the middle of the line for the Giants.

"It's just a shame. I hate to see (it)," Coughlin said. "Obviously, it's your health first, and there isn't any question about that. The only way, I guess, they can control these things are with these drugs, these blood-thinning drugs. Once you do that, obviously you're done. I mean, you can't take a chance on some kind of bleeding that is undetected.

"So, it's just a sad thing."

Rogers, who was examined by team orthopedic surgeon Russell Warren and vascular surgeon John Karwowaki at the Hospital for Special Surgery on Monday, was not immediately available for comment.

Canty said that his knee is improving, but he could not put a timetable on his return.

"We knew this was gonna be a long process. Obviously, I didn't think it would be this long, but I think we're being smart about it, we're taking the right approach," Canty said. "It's important for me to do everything I can mentally and physically to make sure when I do get the clearance to step out on that field I'm ready to go."

While he would like to be on the field for the season opener against his former Dallas teammates, Canty would not guarantee it. He added he would not need a lot of time to get ready after seven years in the league.

"I'm not gonna rule it out, it's still a possibility," he said. "Obviously, I would definitely look forward to being out there opening day with my guys being able to hunt. We'll see."

Austin, who missed last season with a torn pectoral muscle, participated in both the practice and walkthrough on Monday.

"I'm praying that when the phone call comes, it's a good one. That it can be controlled and all that business," said Coughlin, who received a call Monday that Austin needed to be seen by doctors. "But I haven't heard a word, not since he left."

Back injuries have been a problem since camp opened in late July. Cornerback Terrell Thomas missed the first workout after his back stiffened and offensive tackle James Brewer and Austin also missed time with back problems. Offensive tackle Will Beatty came to camp with a back issue, and Parker's back seemingly is a football-related injury.

Still, Joseph complained about the mattresses the team provides for the players.

"Everybody has been complaining about their back because the beds in the dorm are fairly hard. My back (is) hurting, too," Joseph said. "I think it is just the bed. We will see. Marvin went to the doctor today. I don't know what is going to happen with him or what is going on with him. I am praying for him and hopefully it is just the bed and we will go from there."

Giants spokesman Peter John-Baptiste said none of the players had complained about the mattresses before Tuesday.

Tight end Martellus Bennett said his back was fine, but he added the mattresses and beds are still small.

"We're big humans," he said. "Every bed is small. You can't put a dinosaur in a twin-sized bed."