The Patriots have already replaced Wes Welker with a younger model
Former Rams WR Danny Amendola has signed with the Patriots for five years and $31M. $10M of it is guaranteed.
The Patriots didn't really save any money, since Welker and Amendola signed for virtually the exact same yearly salary. They did, however, get a considerably younger version of Welker. Amendola is 4 years younger than Welker, and has a lot less milage on him.
Some people are concerned with the perception that Amendola is injury-prone, since he has only played in 12 games over the past two seasons. However, it's worth keeping in mind that much of the time that Amendola missed was due to a broken clavicle that came millimeters from puncturing his trachea and aorta, which could have been life-threatening. Due to the freakish nature of that particular injury, Amendola had to play it safe and wait to come back.
When he was on the field, Amendola was outstanding. Even in a rather inept offense led by a struggling Sam Bradford, Amendola racked up 63 receptions for 666 receiving yards and 3 TD in only 8 games.
Compare that to Welker, who had one of the best QBs in NFL history throwing his way, and ended up with 118 catches for 1354 yards and 6 TD in 16 games.
Once Amendola develops some chemistry with Brady, there's a good chance that he'll match Welker's production, or perhaps even more.