Of course this does not include Jermaine Wiggins, Torrance Small and Dan Klecko, the only three players to catch a pass from both Hall of Fame quarterbacks, nor Dan Koppen, who played center for both.
Yes, the Patriots kicked the tires on Anthony Gonzalez last season, though he didn't even make it to training camp, and also pursued Reggie Wayne before he decided to return to the Colts, writing this on his online journal:
"Well..... kinda four teams at first. Then three and then two. And you Colts fans don't wanna know who other team was. I'll let you figure that one out. Ha!"
While Adam Vinatieri was the first Patriots legend to cross sides in the rivalry, Welker is the first who can directly and significantly impact not only the two current teams, but a historic NFL debate.
Brady is 9-4 all-time against Manning, but there are still plenty who prefer the Colt who became a Bronco over the Patriot.
They say Manning never had the defensive supporting cast Brady did, while Brady's supporters say he never had the weapons that Manning did in the early parts of their careers.
Manning had the stats. Brady had the wins. At least early on. Later Brady had the stats too.
The argument can be distilled into its simplest terms by whether you can judge a quarterback solely in a vacuum, or if the team around them has to be taken into consideration.
Though Welker, Manning and Brady are all closer to the end of their careers than the start, the receiver's performance will undoubtedly be the latest comparison tool in the great quarterback debate.
There's nothing better than subplots in the NFL, and it doesn't get any better than Peyton Manning taking Tom Brady's favorite target.
The pressure is mostly on Brady, since it's his race to lose, if that's still even possible barring a 19-0 season from Manning, who was last seen throwing one of his signature playoff interceptions.
If Brady can transform another new set of receivers into household names in the latest evolution of the Patriots offense, it will be an impressive note to end his career on, even if he doesn't get a fourth Super Bowl.
But the Patriots' complete receiver overhaul is far from a sure thing, as Doug Gabriel, Chad Jackson, Reche Caldwell, Joey Galloway, Chad Ochocino and now Brandon Lloyd can all attest.
Brady nearly beat Manning with a cast of no-name weapons in 2006, but since then he's always had the ever-reliable Welker, and only lost to Manning with his slot machine once, in 2009's infamous 4th-and-2 debacle.
If Welker's departure signals the end of an era of dominance for the Patriots offense, Brady's detractors will say great receivers like Randy Moss and Welker were as much responsible for Brady's success from 2007-2012 as his defense was from 2001-2006.
Manning has it easy. Welker fits exactly what he needs at this stage of his career, someone who can get open consistently underneath. And with Demaryius Thomas and Eric Decker on the outside, Welker should have favorable coverage to work against.
Barring injuries, it seems assured that Welker and Manning should be just as unstoppable as Brady and Welker were.
It's unlikely, but if Welker just doesn't click with Manning like he did with Brady, a lot of credit would have to go to New England, especially Brady.
Tom Brady holds the trump card if his offense doesn't miss a beat despite Welker's departure. Whatever Josh McDaniels is planning for 2013 and beyond will have a far greater impact on the Brady-Manning debate than anything Manning and Welker do together.
Welker's defection from New England adds another fascinating twist to one of the greatest NFL debates of all time, and the first major direct tie between these two Hall of Fame quarterbacks.
But regardless of Welker's performance in Denver with Manning, the rise or fall of Brady's fourth-generation passing offense could be the final nail in the Brady vs. Manning debate.