In response to Paul_K's comment:
Welker, as a tiny receiver, knew well the danger of playing the Hunger Game. Fortunately for him and for his bank account, the New England Patriots rescued Welker in the prime of Tom Brady's career.
Tom is a pinpoint, short zippy pass thrower and a smart guy. Whenever he hit Wes with a pass, Wes had a full two or three steps to either dodge a big hit or go down.
Wes, as a tiny receiver, had a policy of always going down fast if he had the first down, rather than taking the big hit. He talked BB and TB into allowing him to voluntarily hit the turf rather than take a hit from the other team's enforcer. BB could see the relative advantages of ball protection and receiver protection. And so Wes had a number of good years with the Pats, marred by a simple untouched slip and fall on Houston's horrible turf which wrecked his ACL.
Wes couldn't turn down the big Hunger Game money. Peyton Manning in his twilight is a guy who can't put any zip on the ball whatsoever. As a result, defenses often have an extra half-second to get to Wes and hit him while he's defenseless.
I can believe that Welker is brain damaged. It's a shame. It happens a lot, and it's getting more prevalent as more NFL players realize the rules of the Hunger Game. Injure and win, or you don't get paid.
It could have been prevented with a "you break it, you pay for it" NFL rule.
It could have been prevented with oversized concussion-minimizing helmets that reduce gee-forces on heads.
It's a free-market shame.
Paul, I'm not sure if you are making a statement that smaller players might be more inclined to have head injuries. The past history of players with serious head injury proves that isn't the case. Mike Webster the center for the Steelers from the 70's was featured in the book, "League of Denial" recently written about this subject. Even a guy like Kevin turner who I kind of thought was small was actually 230 lbs in his playing days.