My gut instinct tells me that it's not going to be Antonio Brown, but Mike Evans, who is going to start getting mad about the crowded receiving core. Throughout his career Evans has almost always seen the Lion's share of the targets, but that doesn't seem to be the case now. Before this year Evans averaged ~9.4 Targets per game, coming out to about 5.2 Receptions/game.
So far this season Evans has been limited to only 5.6 Targets/game, which has netted him about 3.6 receptions/game. He's had four games this season where he's been limited to only 4 or less targets which has converted to only 6 catches over 4 games (4 targets for 3 rec and 0 TD's in last 2 games). He's getting some red zone targets and has 6 TDs to show for it, but his target share is WAY down. Now with AB coming into the picture that will presumably decrease his share even more.