Brandon Aiyuk, WR, San Francisco 49ers1 of 7AP Photo/Ben VanHouten, FileWe'll open our list with the most obvious candidate in the NFL. Brandon Aiyuk's split with the San Francisco 49ers has been inevitable since he and the team clashed over his recovery from a torn ACL last season. He has repeatedly attacked San Francisco, and even the NFLPA, in social-media posts that have left some wondering if he really wants to continue his career. "Instead, he's been firing missiles from a social media bunker, and allowing the 49ers to move forward without him." If Aiyuk does want to continue playing, he'll have to do it outside of San Francisco.