Seems to me that every situation is unique, in terms of the standing of individual players, in terms of the state of the team at a given time, and in terms of what potential replacement players are available in the market at that time. So, it's really difficult for me to speculate based on what the Pats did or didn't do wrt Watson or any other player when they entered their contract year. Maybe they simply kept Watson because, at the time, the alternatives weren't very good (it's not as if the Pats hadn't been actively trying for awhile).
I can see how a rumor regarding Welker might get started from the ATL fan side. Seemed pretty clear to me that Matt Ryan could have used a couple more good passing targets this season. Their only viable slot guy is Brian Finneran and he's about 112 years old now. So, there's probably a significant "wishful thinking" component here on the part of Falcon fans. Then there's the Dimitroff connection which seems to lend an air of realism to all this, whether or not it does in actual fact.
WRT whether or not the Pats would consider trading Welker and/or acquiring another receiver, I start by breaking down what the Pats offense has for targets on the current roster and what areas they regularly work successfully (more or less).
short/intermediate-range passes, mostly between the numbers:
Welker, Edelman, Hernandez, Gronkowski, Woodhead, (Faulk)
sideline passes:
Branch, Tate
deep zone passes:
Tate
Price is a complete unknown. He might end up being a sideline/deep zone guy, but there's really no way to know for certain.
Seems to me that the Pats could afford to swap out a guy from that first group (lotta redundancy there) for another guy who can regularly work the sidelines and deep zones (could be either draft or FA). Welker is certainly the oldest of that group, but also the most reliable. Edelman maybe has more upside and is certainly the better PR, but also seems to get injured often. In any case, spreading the attack out across more of the field would seem like a good thing at this point (regardless of the anomalous "Moss situation").
Not sure how the trade economics would work out. I can't imagine that the Pats would accept less than a 2nd for Welker. Maybe that works for ATL - getting a proven commodity for a 2nd that they might otherwise spend on a WR in the draft (out of a fairly weak WR class).
It really comes down to how BB and the coaches feel about Price and Edelman (and Tate), and/or how they feel about a WR they might pick up in the draft/FA this year or next.
Nothing can happen anyway until a new CBA is signed, right?