Only seen him take a few good punches on his feet. Chael hit him in the first fight and Anderson fell back hard( and Charl has pillow hands) and Chris KO'd him
It could be that because of Silvas great movement he's masked the fact that he doesn't take punches well
Could more KO's be in his future because of aging and speed lose? 
Great chin. Has hardly taken any concuss-ing damage to the brain. Honestly this is the first time he's ever been close to being concuss-ed.
I just think it's time to put the showboating away and take every opponent serious from here on out. 
He has a pretty solid chin, and he's got the Raging Bull thing going on where he can roll with punches to an insane degree.
Some people just eat bad shots and this had bad shot written all over it.
He was full leaned back so he couldn't roll with the punches, and that backhand nudge Weidman landed set up the left hook so AS kinda moved into it. Not to mention he just didn't see it coming which is a huge part of absorbing blows.
When you don't realise a shot is coming your much less able, supposedly, to absorb the shot.