Before Wes Welker got to New England, Tom Brady had never accumulated a quarterback rating of better than 92.6 in any season. Even as the Patriots went 12-4 in 2006, Brady's quarterback rating of 87.9 ranked him ninth in the NFL -- behind, among others, Damon Huard, Tony Romo, Carson Palmer, Marc Bulger and Philip Rivers.
Wes Welker changed all that.
In the two seasons in which Brady and Welker have played together -- keeping in mind that 2008 was very abbreviated -- Brady has been a significantly better quarterback with Welker on the field than without him.
Welker missed Weeks 2 and 3 and left the Patriots' Week 17 early enough that Brady essentially played the entire game without him. Consider these numbers:
Brady without Welker (Weeks 2, 3 and 17)
Completion percentage: 56.5 percent
TD-INT ratio: 1-2
Quarterback rating: 69.4
Brady with Welker (2007, Weeks 1, 4-16 of 2009)
Competion percentage: 68.5 percent
TD-INT ratio: 77-19
Quarterback rating: 110.9