Sunday's practice proved that competition in the Green Bay Packers' secondary has reached a high intensity.

"Everybody's trying to make a push," Nick Collins said.

The Packers released safety Arturo Freeman -- an indication of how heated the battle for roster spots has become.

Many observers thought the veteran Freeman could end up as the starter at strong safety because of his experience with the defensive scheme. He had spent his entire five-year career with the Miami Dolphins under defensive coordinator Jim Bates.

His release, however, will allow the Packers to take a more extensive look at other players.

"We just felt like we had to go in another direction, had to get the safeties' numbers down to where we could get more evaluation in the next three games," Bates said.

By letting go of Freeman with three preseason games to play, the coaching staff hopes he can hook on with another team. Bates said Freeman already has received several phone calls from interested teams inquiring about his services.

Freeman's release could open even more time for Collins. The rookie second round draft pick and Mark Roman started on Sunday.

Collins said he has mastered the playbook quickly but wants to hone his technique. He must become more adept at reading the quarterback before nailing down a spot in the highly competitive starting safety derby.

"He's making progress as a lot of the other safeties are making progress," Bates said. "It's still a wide open race. It hasn't been determined yet whose going to be the starters."

The team also released Freeman to give rookie Marviel Underwood, a fourth-round pick, more opportunities.

Sherman said Underwood is still learning the scheme. He, however, impressed the coaching with his range and hitting ability.

"There are a lot of positives there," Sherman said. "He just need reps and experience at doing his job."

Safety is not the only secondary position up for grabs. Joey Thomas, the starter at left cornerback going into training camp, returned to practice from a calf injury. In his absence, Ahmad Carroll, a first-round draft pick in 2004, worked with the first team. Sherman also praised Carroll's performance against the Chargers on Friday night.

"Ahmad and Joey are still going to battle for the job," said defensive nickel package and cornerbacks coach Lionel Washington. "A lot of things could happen."

As expected Thomas showed some rust during Sunday's practice but still can become the starter if he displays more consistency.

"He was doing a great job before he got injured," Washington said.

Thomas spent about 20 minutes after practice working on his technique with Chris Johnson, Chris Day and Washington.

"He should catch up. Today was a good start," Bates said of the second-year player. "Physically he looked like he was ready to go."

Cornerback Chris Johnson also returned to practice on Sunday after passing his physical on Saturday.

A knee injury destroyed his chances of landing the nickel cornerback position in 2003. In 2004, he sustained a stress fracture while rehabbing the same leg. A shin injury had curtailed his 2005 season.

"I consider myself a rookie because I haven't played a down in the NFL yet," Johnson said. 'I' m feeling pretty good. I came out today just trying to get my legs under me a little bit and just trying to compete."

Johnson took advantage of his time off and gained a better understanding of the defense. He studied the formations and personnel from the sideline.

"Now once I get out here I can react instead of just thinking all the time," he said.

But Johnson will have to perform on the field because the Packers have staged a fierce battle for the team's secondary positions.

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Special Teams Becoming Special

Before Friday's preseason game, San Diego Chargers head coach Marty Schottenheimer raved about the performance of his rookie returner, Darren Sproles, a 5-6 burner.

His results? Three returns for three yards.

"I think our special teams really did a phenomenal job," Sherman said.

Sherman attributed the extra time spent working with younger players on special teams technique before, during and after the organized team activities.

That work could help several players gunning for the final roster spots. The fourth and fifth linebacker, third tight end, second fullback, fifth cornerback and third tailback likely will have to be significant contributors on special teams.

"There are a lot of positions special teams plays into," Sherman said.

Much-maligned punter B.J. Sander also had his best performance to date versus the Chargers, booming seven punts. He averaged 46 yards.

"I don't know if we've ever played that well this early on special teams," Sherman said.

**

Quick Hits:

Wide receiver Terrence Murphy (hip) and linebacker Brady Poppinga (hamstring) returned to practice on Sunday. ... Defensive tackle Donnell Washington took some snaps with the first team. ... When linebacker Ray Thompson left practice, rookie middle linebacker Roy Manning switched to outside linebacker. ... "We dropped too many balls today," Sherman said. "That's uncharacteristic of us in practice."... Rookie William Whitticker, a seventh-round pick, continues to take most of the repetitions at starting guard. Sherman complimented his improved pass blocking. "He's certainly answered the bell when we asked him to make plays for us," he said. "He still has a lot of work to do and a long way to go, and we're still evaluating everyone at this position."