Rich Cimini's recent article about how Darrelle Revis shut down Reggie Wayne offers a perfect illustration for what the best cornerback in the NFL can do when assigned to take an opposing team's best receiving weapon out of the game.
With that thought in mind, it would seem like the highest percentage play for this weekend's matchup against the New England Patriots would be to send Revis after Wes Welker. Welker's 122 targets easily gave him the team lead in that category and shows that he is often Tom Brady's first target choice on a play.
The issue in doing that is that Welker is most certainly not the most dangerous wide receiver on the New England roster. That honor goes to Deion Branch.
Proof of this can be via a metric review. Welker is known as one of the most dominant possession threats in the NFL, but Branch beats him in short pass yards per attempt by a yard and a half margin (8.1 YPA for Branch, 6.6 for Welker). (Note: a short pass is defined as one thrown 10 yards or less)
Branch is also just as productive after the catch. According to the Patriots' team stats page on ESPN.com, Welker has 411 yards after catch (YAC) on 86 receptions, or 4.8 YAC per reception. Contrast that to Branch's 234 YAC yards on 48 receptions, or 4.9 YAC per reception, and it shows that these two are nearly equal in their run after catch abilities. (Note: Branch's totals are for his New England tenure only)
Where these two were not equal this year was in the area of vertical pass productivity (vertical passes being those thrown 11 or more yards downfield). Branch caught 18 out of the 33 vertical passes thrown his way and gained 404 yards and four touchdowns. Add in a 29-yard pass interference penalty and it means Branch tallied 13.1 YPA on vertical throws.
Welker fared fairly well in this area, catching eight out of 16 vertical passes for 177 yards, or 11.1 vertical YPA, but his lack of downfield targets indicates he is not utilized as a stretch the field receiver (no surprise there).
What this all means is simple. Putting Revis on Welker would take away a strong short pass threat but putting him on Branch would take away both a short threat and a long threat. It's like placing two castaways on Revis Island instead of one.