The NFL and its referees' union are racing against the clock to hammer out a new labor deal ahead of a May 31 deadline, and things are ... not going well. Negotiations have stalled in recent days, and the league has since begun preparing to hire replacement officials to use during training camp and beyond in the event of a lockout.
But how exactly did we get here, and what are the issues at the heart of the dispute? Let's take a look:
