SAN DIEGO -- Chargers tight end Antonio Gates tested his surgically repaired left big toe Monday at training camp and said it's about 65 to 70 percent healed.

While rookies and select veterans opened camp, Gates went through a 45-minute workout on a side field. He tested the toe by running and cutting.

Gates was hurt in a wild-card playoff win against Tennessee and then played against Indianapolis and New England despite being in obvious pain. He underwent surgery in late February to repair what he said was a tear in the plantar plate.

"Obviously, it's a process," Gates said. "I'm a lot better than I felt a month ago. I can say that. I have no determinant on when and how fast I'll be coming back. But right now, I feel good. It's a little sore, but it's tolerable."

Meanwhile, first-round draft pick Antoine Cason officially became a holdout when he missed Monday's workout. Selected 27th overall, the cornerback from Arizona hasn't reached contract terms.

"I wish he was here, but he's not," coach Norv Turner said. "I never try to speculate on progress and are they close or are they not close? There's no such thing in my mind. It's either done or it's not done. I thought it would be done now. It's not."

Said general manager A.J. Smith: "I just hope he's here soon, is all I can say."

Also Monday, Turner said linebacker Anthony Waters underwent arthroscopic surgery on his left knee Friday and will be sidelined two to three weeks. Waters missed last season while recovering from a torn ACL in the same knee while playing for Clemson in 2006.

Gates said it was too early to know whether he'll be ready for the season opener against the Carolina Panthers on Sept. 7. Monday was the third time Gates tested the foot by running, and saw progress when comparing the session to the other two workouts.

"The first time I went out there, I wasn't able to finish the workout," Gates said. "The second time, I finished it, but I was really, really sore. Now it's to the point where I can finish the workout and the next day it will be a little bit sore. As it continues to go on and the progress continues, hopefully I can just get through a workout and feel really good the next day."

Gates caught 75 passes for 984 yards and nine touchdowns last season.

Quarterback Philip Rivers, who played hurt in the AFC Championship Game, said he's fully recovered from the torn anterior cruciate ligament that required surgery.

"I've been going full-go now for over a month," Rivers said. "There's nothing I can't do. There are times throughout the day I can't tell which knee I hurt."

In other injury news, Turner said center Nick Hardwick is making progress from offseason foot surgery, but is a candidate to be placed on the physically unable to perform list. If he were placed on that list and not removed before the start of the season, he would be required to sit out the first six games of the regular season.

Receiver Eric Parker, who missed all of last season with a toe injury, wasn't at the team complex Monday and his tenure with the Chargers could end within the next couple of days.

"If we have any developments regarding Eric, we'll let you know immediately," Smith said.