ENGLEWOOD, Colo. -- The idea that a team would release a four-time MVP who amassed nine consecutive 10-win seasons, including seven 12-win seasons, is pretty jarring.

Of course, it helped the Colts that they tumbled at the opportune moment to draft the best quarterback prospect since their aforementioned franchise QB came out of Tennessee in 1998. But the fact that they released Peyton Manning, an icon of the franchise and already one of the best quarterbacks of all time, when he was still two weeks shy of his 36th birthday says a lot about the uncertainty of No. 18's future at the time.

"I certainly didn't think this would even be a possibility a couple of years ago," Manning said after throwing career touchdown Nos. 507-510 in a 42-17 win over the 49ers last Sunday. "...Our offense has done some really good things here in just two and a half years."

For a player to rebound from a cloudy future -- after having multiple neck procedures and leaving the only professional team he ever knew -- and return to his 11-time Pro Bowl level of play would be quite impressive. But to ascend beyond that level and set new NFL benchmarks with each passing year? That would be incredibly difficult to fathom.

But that's exactly what Manning has done as a Bronco.

After missing the entire 2011 season, Manning's 68.6 completion percentage, 4,659 passing yards and 37 touchdown passes in 2012 all ranked second-best for his career.

The record-breaking figures of 2013, Manning's historic 16th season, have been well-documented, but to quickly recap: 5,477 passing yards, 55 TDs and the 606 points scored by the team all marked NFL records, which he set while also posting the lowest interception percentage of his career (1.5).

And don't look now, but Manning is on pace for 4,878 passing yards and a hair over 50 TD passes in '14 while averaging 5.2 fewer attempts per game than in '13 (36 to 41.2). He's also throwing picks on just 1.2 percent of throws and leads the league in TD percentage (8.7), yards per attempt (8.5) and passer rating (119.0).

Amazingly, if he started from zero and maintained the pace he's set since he arrived in Denver, Manning would pass Brett Favre's 509 career TD passes -- which took Favre 20 seasons to compile -- in just under 11 full seasons.

Most importantly, No. 18 is winning more than he ever has: His 32-7 record as a Bronco (.821 win percentage) is somehow even better than an 89-23 (.795) stretch with the Colts, when he put up an NFL-record seven consecutive seasons with at least 12 wins.

When asked to explain his still-climbing level of production this week before Thursday's game with the Chargers, Manning admitted, "I really don't have a great answer," but cited growing familiarity in his new environment.

"I feel like I've gotten a little better each year than I was the year before due to a little more comfort in this new culture," he said. "Learning Coach [John] Fox's philosophies and it's the second year under [Offensive Coordinator] Adam [Gase], and learning the new teammates."

"I do think as you get more comfortable with your surroundings and the players you are playing with, hopefully that leads to improve play on the field."

Even so, it would be difficult to argue Manning wasn't just as comfortable, if not more so, in Indianapolis, where he had spent his entire career to that point, running the same offense and working with the same targets year after year.

Yes, he has a versatile and deadly set of weapons in Denver, all utilized in advantageous ways by Gase's creative schemes and playcalls. But are the people around him that much better than a historically great crew in Indianapolis?

"I don't really know," Demaryius Thomas said. "He had Marvin Harrison, Reggie Wayne. He had [Dallas] Clark. He had some great players around him."

"I guess it's some of the things you see him doing – he's working out more, he's with the trainers, he's with the equipment guys. It's tough to see a guy like that get better and better. I don't know how he does it but it happens."

Manning's extra attention to his body and the weight room was necessary as he rehabbed from the neck injury that set his career on a different course, but his work has continued in the years since, despite the injury becoming more of a distant memory. Thomas and others noted in the offseason and during training camp that the quarterback's arm is stronger than it's been the last two seasons. Likewise, when asked if he's bothered by the media's perception that he isn't a great athlete, Manning noted that he still has all of the requisite in-the-pocket movements necessary to keep plays alive and make throws under duress.

"I think you do work on things as a quarterback, moving in the pocket, sliding here or there to make a throw," he said during the week leading up to the game against the 49ers. "I think if you can't move at all and you get where you can't bend or you get stiff, that's when I'm not sure you need to be playing anymore."

"I think for a guy that doesn't run very well, being able just to move and slide in the pocket and make certain throws, I think I can still do that."

Perhaps most important to keep in mind in explaining the 17-year veteran's exponential production is Manning's steel-trap memory and close attention to the most miniscule of details, attributes that undoubtedly add up to something tangible over the years.

"I think experience helps," Gase said Wednesday. "He's seen almost everything you can throw at him. It's probably slowed down for him quite a bit."

"And his work ethic's never changed. Maybe a lot of other older quarterbacks feel like maybe they have it and they don't need to work on it as hard, but he works on it like he's a second- or third-year player."

That his unparalleled effort brought with it the special moment against the 49ers, when several NFL legends offered their congratulations to the league's new all-time touchdown king, is the ultimate credit to Manning, who accomplished a goal that once seemed out of reach for a rehabbing quarterback with 14 professional years already past.

Already creating more separation from Favre with No. 510 against the 49ers and three more touchdowns against the Chargers, who knows how high Manning can carry his torrid production.

Perhaps another QB who is familiar with late-career success stories might have an idea. "It's just an unbelievable feat," Executive Vice President of Football Operations and General Manager John Elway said, "but the one thing I would think is I'm planning on him having a lot more touchdown passes."