Jerry Rice is the greatest wr of all time. But even Jerry only has 4 seasons in his career of over 100 catches.I don't know if you will ever get a perfect definition of possession wr. But I think high reception totals with a low catch average equals a good start. Some guys you just see and you think possesion guys and Welker is one of those. What he is doing on a winning team year in and year out is going to end up being quite impressive when all is said and done.
It's a good point. However, I wouldn't called players in Detroit, Atlanta, or Pittsburgh's run and shoot (of the past) great possession receivers in the classic sense of what I think a possession receiver is. When you spread the field and get a lot of underneath stuff in shallow zone coverage the credit goes a lot more to the offensive scheme than the individual effort of the player. Welker is a tough guy with good skills after the catch and he is savvy with crossing routes. However such a high amount of his receptions seem to be crossing routes that it's difficult for me to look at his catch totals and be as impressed as I would be with players like Keenan McCardell, Steve Largent, Charlie Joiner, Chris Carter, and other receivers who faced more man coverage and played on teams where they went over the middle on the more dangerous routes because their system dictated it. A crossing route tends to be more of an east-west over the middle route that is less dangerous and productive than a north-south route requiring little margin for error and more toughness like a skinny post or dig route. I'm not taking anything away from Welker's potential to do these things, but he just doesn't get to prove it the way I think a possession receiver should be defined which is a receiver that runs a higher variety of routes like dig routes, skinny posts, outs, and corner routes and makes those plays in tight coverage or in high traffic areas? Again, it's not his fault he benefits from Randy Moss and Tom Brady. However, Some of the best possession receivers are also players who can function as a No.1 without a great presence opposite him. I'm not sure Welker will have the opportunity to prove it. He's a very good player, but best possession receiver of all-time? I wouldn't remotely mention his name for another three to four years even with his impressive three-year run statistically speaking. In fact, based on toughness, hands, routes, and versatility, I'll take Donald Driver over Wes Welker because he is asked to do more than Welker right now and does it well. Welker will have better stats than Driver, but to me Driver is a better possession guy. Put him opposite Moss and I think you wind up with a more dynamic offense. This is probably why Brett Favre had a near conniption to get Moss in GB a few years ago. Current possession receivers I like as much as Welker

river, Houshmandzadeh (not in the right system for his talents), Jerricho Cotchery, Hines Ward (not a great route runner, but Welker runs limited routes, too - maybe more by design in the offense), Steve Smith (Giants), Lance Moore (when healthy, he's a lot like Welker). If you go strictly by stats then yes, I can see catches and first downs as a factor. However, I believe the stats will be biased towards modern players and systems that force defenses to play softer coverage underneath in the 8-10 yard area off the line of scrimmage. Steve Largent is still a player that comes to mind as a great possession receiver who probably gets a little short shrift due to the fact he wasn't in a pass heavy offense and facing defenses allowed to play bump and run in a manner that we'd hear the media, fans, and coaches term "a mugging" when the Pats did the same thing a few years ago in a championship game against the Colts.