ENGLEWOOD, Colo. (AP) — Peyton Manning looked as though nothing had changed after sitting out last season because of a neck injury. Don't be fooled, though, says the Broncos quarterback — plenty is different.

And not just the horse on his helmet.

Manning insists he's still searching for a comfort zone in Denver and figures his transition after 14 seasons in Indianapolis will take all season. Same with his rehab from the nerve injury that caused weakness in his throwing arm and forced him to miss last season.

Broncos boss John Elway agrees, telling The Associated Press that Manning's arm strength is "probably not where he wants it to be. I don't know if it'll ever be where he wants it to be, but to me, it's plenty adequate right now."

Teammates, opponents, even his former coach, NBC analyst Tony Dungy, who was on hand to chronicle his Denver debut, agreed that Manning hadn't missed a beat.

Appearances can be deceiving, though. Just last week, Manning said, "I have some things that I deal with myself, but I kind of keep that between me and the trainer."

Manning's game, this new offense, his timing with his targets, even his health, are all works in progress, Elway told the AP in an interview Thursday.

"There's going to be adjustments week in and week out," Elway said. "He knew those guys in Indy, those receivers, he had them forever and so it will be a work in progress, to me, as long as Peyton's here, because he's going to change things and there's going to be new things all the time.

"And especially with his rehab and continuing to work because I don't know if he's where he wants to be. It doesn't sound like it is. But I'm not sure if he'll ever get to where he wants to be unless he wins two Super Bowls and he'll say, 'I'm where I want to be.'"

Elway is betting Manning gets to hoist that second Vince Lombardi trophy.

The quarterback's work ethic is "what gave us confidence that he was going to be able to come back and be as close to the Peyton he was of old," said Elway, who spoke to AP while promoting the Dove Men+Care "Journey to Comfort" campaign. "The question was: How fast? And he's made tremendous strides from the time we saw him in March until now. He's just kept getting better and better. Plus, he worked his tail off, and we saw it in training camp. He had a good training camp. The arm's getting stronger all the time, too."

Manning never has been known for throwing frozen ropes like Brett Favre.

"No, he's always been the cerebral guy, and it's the way he plays the game and takes advantage of everything on the cerebral side," Elway said. "And I think the mind never goes backward, unless it gets hit and knocked out or something like that. But that's why it's just a matter of physically if he could get caught back up.

"A lot of it's like riding a bike for him and plus putting in new, different things that he can do because he loves the mental side and the mental warfare that goes on with the game, as we saw last week when he stood there and stared at Troy Polamalu for 20 seconds down in the red zone. So, he loves the mental warfare that goes on and he'll just continue to get better with that."

Elway said he's having a ball watching No. 18.

"He's already in the Hall of Fame. He's one of the best quarterbacks to play the game now and so he's just trying to add to that legacy," Elway said. "Plus, he raises everybody around him because they know that he gives us a chance to compete every time we go into a ballgame. And that's huge for a team, to have that hope. That's what gets everybody fired up and ready to play week in and week out, to know that you can win that game."

Elway said the biggest barrier in Manning's transition is learning a second language at age 36 — the new terminology he had to absorb as the Broncos blended their old power formations with some of the spread formations he ran in Indianapolis.

After a solid preseason, Manning looked as sharp as ever in his Denver debut, completing 73 percent of his passes and posting an AFC-best 129.2 passer rating in a 31-19 win over Pittsburgh last weekend.

"Gosh, like he hadn't missed a beat," was how Atlanta coach Mike Smith described it. "He was very efficient, looked like the Peyton Manning that I watched two years ago when he was playing.

"I thought he had a very good command of the offense, threw the ball extremely well, had some throws off to the wide side of the field that looked like the old Peyton," added Smith, whose Falcons (1-0) host the Broncos (1-0) Monday night. "And watching him run the no-huddle was reminiscent of having to play against him when I was in Jacksonville."

That's the Manning that Broncos cornerback Champ Bailey has seen every day in practice:

"He's back," Bailey said. "He's back and he's ready. I've never seen a guy work as hard as him. I look forward to good things every week."

Three Broncos who played with Manning in Indianapolis are hard-pressed to find any fissures in the game of the four-time MVP who's coming off four neck operations.

"Well, nothing's different really, I guess the uniform," running back Lance Ball said.

"He's getting better every week, but he's the same guy," said tight end Jacob Tamme.

"To me, he looks the same," said slot receiver Brandon Stokley. "But Peyton, he's the type of guy that's always going to say he's got more work to do and he needs to get better. So, that's just the way he is."

That's what makes him great, Ball said.

"Any great player will always be critical of themselves and always see that there's room for improvement," Ball said. "You can never be perfect."

Dungy said it looks like opponents will have to deal with Manning and his no-huddle offense for years to come. And Elway, who won his two Super Bowl titles at ages 37 and 38, said he believes Manning can be as good in Denver as he ever was in Indianapolis.

"He's not a guy that gets hit a lot and he plays a cerebral game," Elway said. "And so, that's why to me he can play as long as he wants to play and he feels like he's living up to the standards that he's set for himself. And he'll be the one that determines that."