Starting safety Marquand Manuel's nagging calf injury finally healed enough to allow him to hit the practice field Monday for the first time in camp, and the timing of his return couldn't have been better.

Head Coach Mike McCarthy confirmed that fellow safety Marviel Underwood is out for the season with the knee injury suffered on the defense's opening series at San Diego on Saturday. Surgery will be scheduled soon.

Underwood had been taking Manuel's spot with the No. 1 defense with Manuel getting two weeks of what are often called "mental reps," going through every play and defensive call in his head on the sideline.

"I've been getting a pretty good feel," said Manuel, who wore a black rubber sleeve on his troublesome right calf and iced it after practice. "Being an older player, you just need to know where you need to be. I think that's really the key, and now the guys are starting to trust me."

Manuel, a free-agent acquisition from the NFC champion Seattle Seahawks, hated missing practice. But staying mentally involved on the sideline helped him get on the field as a rookie sixth-round draft choice in 2002 with Cincinnati, so he understood the benefits and never let his frustration interfere with his focus on learning the Packers' defensive scheme.

"Playing the calls when I was on the sideline -- getting back in there my depth might not be the same or I might not react as fast -- but it kept me sharp and in tune with what was going on," he said.

Secondary coach Kurt Schottenheimer said the most important thing for Manuel is developing communication with fellow safety Nick Collins and the cornerbacks so the entire secondary can operate smoothly. But he's not expecting there to be a lengthy transition period with a veteran of Manuel's ability.

"He's a very smart player and he understands good communication, the importance of it," Schottenheimer said. "He's a great talker out there. He's always going to let you know down-and-distance, let you know the personnel. He's going to anticipate different plays based on formations and that kind of thing."

Green in team drills

Running back Ahman Green participated in team (11-on-11) drills for the first time since returning to the practice field last week.

Green had been limited to position drills and seven-on-seven and continues to progress as expected from the torn quadriceps tendon sustained last season.

"Today was a good day," Green said. "My goal is to take steps forward and not have any setbacks."

Green looks to have all his speed and cutting ability back and he'll continue to add more reps in practice as long as he continues to feel good.

The Packers' new zone-blocking run scheme also looks more fluid with Green running the ball. Green ran behind a zone scheme between the tackles in college at Nebraska.

"He's a one-cut back, north and south, puts his foot in the ground and that's what you're looking for in the zone scheme," McCarthy said. "It's a one-cut decision-making process and that's his style of running. He's a perfect fit for the scheme."

Green said the goal remains to be ready to play in the third preseason game, at Cincinnati on Monday, Aug. 28. He plans to participate in the full-contact team drills in pads on Tuesday night.

"Right now we've been hitting all our goals, and that's what makes me very happy," he said. "Just taking baby steps one day at a time.

"I've been very patient. I haven't been pushing trainers or doctor, just listening to what they have for me rehab-wise and sticking to it by the book."

Injury update

Running back Samkon Gado, who pulled a groin muscle at San Diego, did not practice Monday and wasn't sure when he'd return. The good news is it's just a muscle pull, not a tear, and Gado said he's feeling fine.

"They didn't give me a time frame," he said. "It could be days, it could be weeks, you just never know with groins. It all depends on how you attack the training and the rehab."

Gado said he got hurt in the third quarter when his foot got caught underneath a player and his leg twisted. He played one more play and limped off, fearing the injury was much worse.

"The rule of thumb is they wait 48 hours before they start doing anything, and it hasn't been 48 hours yet," he said. "But if I feel this good before 48 hours, I feel very optimistic about getting back on the field real soon."

Of the other injuries sustained on Saturday, defensive tackle Kenderick Allen (abdominal muscle) remained out. Defensive tackle Ryan Pickett (finger) and tight end David Martin (hand) returned to practice.

Receiver Leo Bookman (ankle) also returned to practice. Linebacker Kevin Schimmelman and fullback A.J. Cooper sat out for unspecified reasons.