Wes Welker hit from Earl Thomas during Peyton Manning interception should have been flagged

Denver Broncos wide receiver Wes Welker was the victim of a brutal hit by Earl Thomas on Peyton Manning's fourth quarter interception. And while the Seahawks played a good game overall, in my admittedly biased eyes, this was a personal foul on a defenseless receiver.

From the NFL rulebook, the definition of a defenseless receiver includes:

A receiver attempting to catch a pass; or who has completed a catch and has not had time to protect himself or has not clearly become a runner. If the receiver/runner is capable of avoiding or warding off the impending contact of an opponent, he is no longer a defenseless player...

Cleary Welker is defenseless here. And it looks to me like he gets hit in the head by Earl Thomas, a blatant violation of the defenseless receiver rule (also from the rulebook):

(b) Prohibited contact against a player who is in a defenseless posture is:

(1) Forcibly hitting the defenseless player’s head or neck area with the helmet, facemask, forearm, or shoulder, regardless of whether the defensive player also uses his arms to tackle the defenseless player by encircling or grasping him...

Welker wasn't happy with the no call on the INT. He got jacked.

— Vic Lombardi (@VicLombardi) September 22, 2014

Kam Chancellor's interception would have stood, but a 15-yard penalty might have made a big difference in a (at the time) five-point game. Maybe all the difference.

What do you think? Was it a personal foul?

(Gracias for the GIFs, The Big Lead).