After spending six years with Brady in New England, the Pro Bowl receiver agreed to a two-year, $12 million deal Wednesday to team up with Manning in Denver.
The Welker signing was the highlight of a big day for the Broncos, who once again made a major splash in free agency. Welker will hold an introductory news conference on Thursday afternoon.
Denver also came to terms on a two-year deal with defensive tackle Terrance Knighton, formerly of Jacksonville, and a one-year contract with linebacker Stewart Bradley, who played with the Cardinals the past two seasons. Later in the evening, the team added cornerback Dominique Rodgers-Cromartie with a one-year deal.
Last year, the Broncos won the high-stakes contest to sign Manning, prompting Broncos boss John Elway to quip, "Plan B? I don't have a Plan B. We're going with Plan A."
Coming off a 13-3 season during which the Broncos looked like a Super Bowl contender before losing to Baltimore in the division round of the playoffs, Elway is clearly on the same path this time.
He picked up the league's most productive receiver to play in the slot where Brandon Stokley was last season. Welker's five 100-catch seasons are the most in the NFL. He has been selected to the Pro Bowl in each of his past five seasons and was an All-Pro four of the past five years.
"When you look at Wes in the middle of the field, you can't cover him," Elway said. "He does such a tremendous job of getting open, finding seams in zones, beating man-to-man coverage. So, he'll be a huge asset for us inside."
Welker caught 118 passes for 1,354 yards and scored six touchdowns last year, helping the Pats go 12-4 and make the AFC title game before they also fell to Baltimore. He developed quite a rapport with Brady during his six seasons with the Patriots.
The Broncos are banking the same kind of relationship can blossom between their 37-year-old future Hall of Fame quarterback and his newest target, Welker, who is 31.
That the Broncos are signing a top player away from New England certainly didn't hurt, either.
"Anytime you can take a player from a team you have to compete against, it helps, especially the calibre of Wes Welker," Elway said. "New England is there year in and year out and that's a team we have to beat to get where we want to get."
Although the deal with Welker received a bulk of the attention, the Rodgers-Cromartie, Bradley and Knighton deals could also influence Denver's starting lineups.
Rodgers-Cromartie played for Philadelphia last season and had three interceptions. He very well could line up opposite of perennial Pro Bowl Champ Bailey next season.
Bradley played last season for Arizona, where he didn't fit in with the team's 3-4 scheme. His best season came in Philadelphia in 2008, when he had 108 tackles. He will compete with Nate Irving and Steven Johnson for Denver's starting middle linebacker spot.
"Obviously, the standards on both sides of the ball are high here," said Bradley, who found out he was cut from the Cardinals while on his way home from his honeymoon. "I think it's a great combination when you can have a stout, strong defence on a team with a prolific offence."
One that's only bolstered by the presence of Welker.
"The Welker deal is a big deal. He's a great player and just another weapon on an already scary offence," Bradley said. "He's definitely a dangerous player because you think he's covered and you throw the ball to him, he's going to catch it. He's so versatile in the slot. He's a durable guy. He has been as productive of a guy as there is in the NFL in the past five or six years.
"I think he'll be a great addition to the team."
Knighton couldn't agree more.
"Wes Welker, (Eric) Decker, Peyton Manning, (Demaryius) Thomas — that will be hard to deal with for any defence in the league," Knighton said. "There are a few teams in the league that you could say actually have a chance of playing in the Super Bowl and this is definitely one of those places."
Knighton was a third-round pick of Jacksonville in 2009, when Broncos defensive co-ordinator Jack Del Rio was there. His signing, along with Tuesday's resigning of Kevin Vickerson, gives the Broncos 600-plus pounds of defensive linemen to plug holes in the middle.
"Jack used the word 'stout.' He needs stout," Vickerson said. "He wants us to be stout. Stout in the inside. No movement."
Knighton, whose nickname is "Pot Roast," can definitely help in that area.
Just to be clear, though, he signed at the same time as Welker.
"I'm pretty sure his news is bigger than mine," Knighton said, laughing. "I'm just excited about the addition and just ready to get things started."
The loss of Welker caught some in the Boston area a little bit by surprise.
"Say it ain't so, Wes!" Celtics coach Doc Rivers said before their game against Toronto. "He was fun to watch."
To open free agency on Tuesday, the Broncos solidified the offensive line by bringing in guard Louis Vasquez on a four-year contract worth $23.4 million, with $13 million of that guaranteed.
AP National Writer Eddie Pells in Denver and AP freelance writer Ken Powtak in Boston contributed.