The NFL always wants the players on each team to look as much alike as possible during games. The league has fined and/or prevented players from wearing certain colors or decorating their face masks or cleats to promote (often entirely worthy) causes before, so it shouldn't come as a surprise that Antonio Brown was fined for wearing cleats that were a different color than the rest of his teammates' cleats earlier this season.
What is somewhat surprising is that Brown said a ref threatened to sit him down for the rest of the game if he emerged from the locker room for the second half of the Steelers' game against the Eagles on Sunday wearing the same light blue cleats he wore in the first half. The spikes had pictures of Brown's four children, Antonio Jr., Antonio, Ali and Antanyiah painted on them.
And change the cleats he did. Here he is in the second half, in standard white, black and gold cleats:
For what it's worth, Brown caught five of seven targets for 55 yards before halftime, then secured seven of 11 targets for 85 yards during the second half.