Billy Horschel isn't apologizing for his criticisms of Chambers Bay or the USGA, but he is apologizing for his actions on the sixth green Sunday.
After a bogey on No. 6, Horschel appeared to slam his putter directly onto the putting surface, although it was unclear whether or not he actually made contact with the ground. Three holes later, Horschel, after missing a putt, did a kind of interpretive dance that channeled the old Price Is Right game "Plinko."
On Monday, Horschel took to Twitter to apologize:
I am sorry for my actions on the 6th green yesterday.