The former Patriots wide receiver addressed his current team before Sunday's AFC Championship Game between New England and Denver after coach John Fox asked him to speak last week.
Welker joined the Broncos last offseason on a two-year deal for $12 million, $1 million more per year than the Patriots offered.
After spending six seasons as Tom Brady's top target in New England, Welker was Manning's leading receiver before missing the final month of the season with a concussion.
He still finished with 73 receptions for 778 yards and a career-best 10 touchdowns and added a touchdown in Denver's 24-17 win over San Diego in the playoffs last weekend.
After an unhappy homecoming at Foxborough in November, when his blunder on a punt in the wind led to a 34-31 loss to New England, Welker gets another chance to stick it to his old team on Sunday when the Broncos and Patriots square off with a trip to the Super Bowl on the line.
Welker has been asked ever since his arrival in Denver to compare the two quarterbacks with Hall of Fame credentials, something he finds harder to do than to go across the middle with a menacing middle linebacker bearing down on him.
"It's like comparing Picasso and Michelangelo,'' he said last week. "It's hard to compare the two.''
The Associated Press contributed to this report.