Flowery Brach—Mike Peterson is back — with a new nickname.

Just call the Falcons' linebacker "Unc." All his teammates have taken to the moniker for the 14-year veteran, who was brought back last week when Lofa Tatupu was lost for the season with a torn pectoral muscle. It was a torn triceps muscle that ended Peterson's season — and nearly his career — last year.

"I'm everybody's uncle around here now," Peterson said Thursday following the Falcons' first day of training camp.

Peterson spent the past three seasons with the Falcons, but was not re-signed after suffering the season-ending injury. He began the rehabilitation process and waited for a phone call. And waited. And waited.

"I can't say that I considered my career over, but I have to be honest, you have that in the back of your mind," Peterson said. "You keep pushing through it, keep training, keep rehabbing and wish for the best. Especially when you feel you can still play a little bit."

Peterson, who turned 36 last month, said he had calls from other NFL teams inquiring about his health and the status of his rehab, but that he always wanted to come back to the Falcons. He was available when they called and put him through a physical.

He is back on the field, wearing his No. 53 jersey, and back in the locker room, where he has re-assembled the Falcons D-Block. That's the self-titled name for the linebacker group.

"With Mike Peterson there is a comfort level because he's been in our system," coach Mike Smith said. "He's been in our locker room. He's been a leader. He is a guy who can play all three [linebacker] positions. He'll be a great mentor to the young guys."

Peterson missed the Falcons' final regular-season and playoff games, which he called the toughest part of the injury. He added it wasn't going to be down for long.

"I wasn't looking for a pity party," Peterson said. "I just put my head down and got to work."

Nicholas back

Linebacker Stephen Nicholas was back after off-season surgery to repair a toe injury that kept him out of organized team activities and minicamps.

Nicholas was running with the first-team linebackers Thursday.

"I thought I might be ready for the last minicamp, but we took our time and I'm ready now," Nicholas said.

Holmes also back

Offensive lineman Lamar Holmes also was cleared to begin practice just in time for training camp. Holmes, the team's third-round draft pick this year, said he suffered a broken foot while running just weeks after being drafted.

"I thought I was doing the right thing," Holmes said. "I tried to finish the end of my run strong, and I felt something in my foot, and that's what it was."

Holmes acknowledged it will take a little while to get back in the swing of physical football.

"I've got some rust," Holmes said. "I haven't been in pads since the East-West Shrine game. I haven't done any real physical activity since then so there is a little rust, but I'm going to get it off before you know it."

Pads on Saturday

The Falcons did not practice in pads Thursday, a byproduct of the new collective bargaining agreement. By rule, teams must wait three days, including reporting day, before a padded practice is allowed. The Falcons will hit for the first time in Saturday's afternoon session.

Early look at the O-line

There were no changes to the Falcons' first-team offensive line with the opening of training camp, but two rookies took a step forward.

The starting unit remained Sam Baker, Justin Blalock, Todd McClure, Garrett Reynolds and Tyson Clabo. However, Peter Konz, the team's second-round draft pick, practiced with the second unit at right guard behind Reynolds. Holmes practiced with the third unit at left tackle behind Baker and Will Svitek.

Rotating defensive backs

Brent Grimes and Asante Samuel rotated between left and right cornerback at times during Thursday's practice. In nickel packages, Dunta Robinson moves inside, and Samuel plays right cornerback. However, on a number of nickel alignments Samuel moved to left cornerback, the spot normally manned by Grimes. It's all part of defensive coordinator Mike Nolan's multiple-look packages.

Full roster

All 90 players on the training-camp roster reported and were on the field for the team's first practice. Defensive tackle Corey Peters (foot) was in attendance after being placed on the active non-football injury list. Smith reiterated Thursday that Peters was injured off campus before off-season workouts and will be re-examined in three weeks.