ENGLEWOOD, Colo. —Peyton Manning understands how Tom Brady must have felt, to scan the huddle and wonder, "Who are these guys?"
Part of it is that because both are in their mid-to-late 30s (Manning is 37, Brady is 36), they've outlasted many of their old teammates. And part of it is how the business side of football and free agency has forced the two quarterbacks to adapt.
As Manning and Brady resume their friendly rivalry Sunday in Foxborough, Mass. — their 14th matchup since 2001 — consider just how much their football worlds have changed.
For Manning, it was a new city and a roster full of new teammates. Manning has had two offensive coordinators in his two years with the Denver Broncos and has survived the loss this season of two centers and all-pro left tackle Ryan Clady to injuries.
For Brady, while he's remained the face of the New England Patriots, he was asked to maintain the status quo in Foxborough despite losing four of his top five receivers from an offense that ranked No. 1 in the league last season.
So much for a pair of elite quarterbacks just cruising through the final years of their careers. For Manning and Brady, the changes have meant even more work, a willingness to be flexible and, yes, plenty of patience.
"You have a new coordinator and new players, and that means new ideas, new plays, and so from that standpoint, everybody's really had to study and be on top of their game mentally," Manning said. "Guys have done a good job of adapting. It's a credit to those guys for kind of learning on the run and doing and executing the offense in a relatively new system."
Brady could only sit back and watch as the Patriots offense changed around him. Wes Welker, who had 118 receptions for 1,354 yards in 2012, and the Patriots couldn't agree on a contract before free agency kicked off. He bolted and signed with the Broncos in March. Rob Gronkowski, the all-world tight end, endured surgeries on his forearm and his back that kept him out until mid-October. Aaron Hernandez, Brady's other star tight end, was cut after he was arrested in June on murder charges.
The Patriots signed Danny Amendola to try to replace Welker along with veteran Julian Edelman, surrounded Brady with young receivers including Aaron Dobson and Kenbrell Thompkins and tried to rely on a running game with Stevan Ridley and Shane Vereen, who returned to the active roster last week after injuring his wrist in the season opener.
Yet it has taken far longer than anyone, certainly Brady, would have hoped to see the offensive results. The Patriots did put up 55 points in a win against the Pittsburgh Steelers in Week 9 but were held to 20 in Monday's loss to the Carolina Panthers.
"I'd say our offense is very different than it's ever been in the past. Everything that we do has a different feel to it," Brady said. "We've had so many new players, like every team has new players, but we have a lot of new players. We have different schemes. We're trying to find different things that work."
Manning can understand those growing pains. He was there a year ago, arriving in Denver after his release from the Indianapolis Colts, where he had spent so many years with a familiar group of teammates. Instead of seeing Reggie Wayne and Dallas Clark, Manning was staring at Demaryius Thomas and Eric Decker.
With Manning and the Broncos on pace to break multiple offensive records, including Brady's single-season record of 50 touchdown passes, it's hard to remember that the quarterback and Denver struggled early last season. The Broncos lost three of their first five games with Manning, including 31-21 to Brady's Patriots in Foxborough.
"All I know is when I've played with new receivers, every single practice, every single walk-through, it's just so important," Manning said. "Yet experience is still your best teacher. What you like to do is try to get as many different situations and experiences early in the season and use those to your benefit in the second half of the season."
Wednesday, Thomas recalled how, despite an intense set of offseason workouts and training camp, it took until midway through the 2012 season to truly gain Manning's trust.
In an offense predicated on timing, Thomas and his teammates had to prove to Manning that they would be at an exact spot at the exact moment Manning wanted them to be there.
"It probably got better as the season went, but it took awhile," Thomas said.
It has gotten even better this season with the addition of Welker and the emergence of tight end Julius Thomas, who has a team-high 10 touchdown catches. Welker leads the Broncos with 61 catches, one more than Demaryius Thomas, who leads in receiving yards (914). Decker quietly has averaged 14.7 yards a catch and is on pace for career highs in catches and yards.
All the changes have made this installment of Manning vs. Brady even more interesting because it certainly won't be identical to any of their previous matchups.
Even as the quarterbacks remain the same, the teams around them have evolved.
"We're going to have to be on our game offensively, because their offense is capable of scoring points, scoring points quickly, and certainly if you have a lead, how quickly they're able to come back because of Tom and that offense," Manning said.