Early odds are Pats by 3.5, 43 o/u.
I'm sure the Welker loss figures heavily in the odds.
Without a Jimmy the Greek or Sam 'Ace' Rothstein to read (for free), that's my speculation. Ravens are a bit beat up too.
In the AFC the first round playoff games are all very close with the injured Patriots having a 53.7 percent chance of beating the Ravens.
Computer simulation =
----- Round1 Round2 Round3 Super Bowl
Patriots 53.7% 21.5% 10.5% 5.1%