INDIANAPOLIS -- Peyton Manning is back. Whether he is ready to play is an open question.

The Colts activated Manning from the physically-unable-to-perform list Monday. A few hours later, the four-time MVP pulled on his white No. 18 jersey and a helmet, and jogged onto the practice field, renewing hopes that he might actually play in the season-opener at Houston on Sept. 11 four months after neck surgery.

"That's kind of been my goal all along, trying to get better and I know everybody's into predictions and everybody wants to have the breaking news," an upbeat Manning said. "But I just can't give you any more than what I'm giving you."

What everyone wants to know, of course, is whether Manning will be ready. Nobody, including Manning, will say that yet and he said again that he won't play in Thursday night's preseason finale at Cincinnati.

Clearly, though, Manning is getting closer. He acknowledged that he is healthy enough right now to take a snap or play a series to keep his consecutive-games streak intact but insists he won't.

"Like I said the other night, I have to be able to competitively play," he said. "I have too much respect for football. I've got to be able to compete and to help my team win, and that's what's fair to the team, fair to myself."

Manning has started 227 consecutive games, including the playoffs, the second-longest streak in NFL history for quarterbacks behind Brett Favre. Of all the numbers Manning has put up over the years, the streak is the one he has usually said means the most.

Manning had been on the PUP since the team's first training camp practice on Aug. 1 following the May procedure to repair a nerve in his neck. The Colts were facing a Saturday deadline to make the move or Manning would have missed Indy's first six games.

Team officials issued a statement that said Manning would practice on a "scripted" and controlled basis. Coach Jim Caldwell did not elaborate on the plan.

"Obviously, he's been throwing, but nevertheless it's just going to be in a limited amount," Caldwell said. "I don't think it needs a whole lot of explanation, I don't believe. Scripted means that we kind of know exactly what he's going to do, prescribed by his rehab specialist and our medical team."

Manning hadn't been seen much at team headquarters, perhaps working out in private. He was at his playful best on Monday, teasing reporters about their memories, poking fun at the circus-like environment surrounding his neck injury and suggesting that his close friend and center, Jeff Saturday, was tired of answering questions about him.

Team officials have said all along that Manning would practice only when doctors cleared him and when Manning felt comfortable, and he again declined to say specifically what was holding him back.

"I don't know what HIPAA stands for, but I believe in it and I practice it," Manning joked, referring to the federal law protecting medical privacy. "So, uh, I'll leave it at that."

The fact he has been activated is not only good news for Manning, his teammates and Colts' fans, but it also eased some concerns expressed by Jim Irsay. Indy's team owner recently wrote on Twitter that the Colts should be prepared to start the season without Manning and later posted comments that prompted speculation he was trying to convince Favre to come out of retirement.