Best value depends on the format
This is a tough one because both players are so similar from a fantasy perspective, but I'll go with Welker in standard leagues and Amendola in PPR formats. Welker, who will now be sharing targets with both Demaryius Thomas and Eric Decker, will be hard pressed to average the 9.96 targets per game he had in New England. Still, he should see enough opportunities in the pass attack to be a viable No. 2 fantasy option in all scoring systems. As for Amendola, he'll take over Welker's slot role for the Patriots and is now a threat to record 90-plus catches. The downfall, of course, is that he's been prone to injuries at the NFL level. The Texas Tech product missed most of the 2011 campaign with an injured elbow, and was forced out of five games last season with shoulder and foot ailments. So while there is clearly more risk with Amendola than Welker, the newest Patriots' PPR upside is going to be too tough to pass on in 2013.
Amendola's in a better fantasy situation
Welker moving to Denver does wonders for the Broncos offense, though it doesn't do much for Welker's fantasy value. He'll slide into Brandon Stokley's role as the team's slot receiver and while I expect Welker to post bigger numbers than Stokely, he's still competing for targets with two quality receivers and a tight end (Jacob Tamme caught 52 passes in 2012). Sure, Amendola has to deal with Gronk and Hernandez (sounds like a buddy cop movie, doesn't it?), but there aren't many other proven targets on the roster. Of course, there are always Amendola's injury issues, but all things being equal, he has more upside in 2013 than Welker.
Amendola's too great an injury risk
I want to pick Amendola. Really I do. And I might if it weren't for one teeny, tiny little thing: Danny Amendola can't stay on a football field. He missed all of 2011 and a good chunk of last season as well. Suddenly now he's going to be healthy? On a side note, I also don't think New England is done tinkering with its WRs just yet. So my vote right now is a shaky one for Welker, who's going to get a ton of looks in the slot because it's what Peyton Manning likes to do, whether it's Austin Collie, Brandon Stokely or someone else. However I don't think Welker will approach his previous numbers in New England due to a crowded landscape, but he'll still be productive. Actually, the value of Demaryius Thomas and especially Eric Decker will decrease slightly as well. I'd still draft Thomas where I normally would, but Welker will drop a round from where he normally goes and Decker could fall two rounds.
Welker improves but Amendola's better
This might be hard to believe, but Welker actually moves up in my rankings. I initially had him at No. 28 because I figured he'd take the fast-money route after he parted ways with the Patriots. So going to Denver actually improves his stock with me a touch. But with Demaryius Thomas and Eric Decker in the mix, it's hard to imagine Welker having a huge season. So I would go with Danny Amendola here. The caveat of all caveats is if Amendola can stay healthy. And he will have to battle with Rob Gronkowski and Aaron Hernandez for targets. But if you made me choose between the two, I'd go with Amendola.
Amendola has greater upside
Amendola. Wes Welker is older and playing on a team with Demaryius Thomas and Eric Decker. The Patriots don't have that kind of talent at wide receiver. Don't get me wrong, it's close. Amendola's injury history concerns me. On the other hand, we're in uncharted waters with slot receivers. The league as a whole has only about a decade under its belt with every club having a slot guy. What kind of longevity does the position -- guys who play the position -- have? It's based on quickness ... 10-yard speed if you will. As players get older, short burst quickness is one of the first things to go. Welker could be getting to that point in his career where he is just not the same player.