Caldwell, 28, had 61 receptions for 760 yards and four touchdowns last season, but also had two key drops in the AFC championship game loss to the Indianapolis Colts.

The Patriots acquired several receivers during the offseason, including Moss, known for his enormous talent, but also for attitude problems. Moss missed all four preseason games with a hamstring injury, but returned to practice today.

Coach Bill Belichick said he wasn't sure if Moss would play in Sunday's opener against the New York Jets.

"We'll see where he is and evaluate it on a day-to-day basis and move forward," he said.

Moss said he has maintained his conditioning, but that sitting out has been frustrating.

"I will not be satisfied until I'm out there with the boys," he said. "That's what I do. I don't cut checks. I don't shine shoes. I don't tape ankles. I play football. That's what I came here to do."

Samuel, who tied for the NFL lead with 10 interceptions last season, returned to practice after signing a one-year $7.79 million contract last week. Samuel held out most of camp looking for a long-term deal after the Patriots applied the franchise tag to him in February, preventing him from becoming an unrestricted free agent.

Samuel's status for the game against the Jets was also uncertain.

"There's a lot of things that he needs to do, but he's working hard at them," Belichick said. "He's been here before and he at least has an understanding of the system and so forth."

Belichick didn't say much about the loss of two key defensive players — injured lineman Richard Seymour and safety Rodney Harrison, who was suspended for violating the league's substance abuse policy.

Belichick didn't elaborate on why Seymour was placed on the physically unable to perform list, saying only: "I think based on all of the information that we had that was the right thing to do. I don't know how else to put it.

Harrison's suspension was "unfortunate," Belichick said, but he refused to discuss it further.

Quarterback Tom Brady said Harrison would be missed.