Two coaches have already been fired, from the Jets and the Saints. Between now and the end of the season, there will be more.

So how many jobs will become vacant?

The current hot spots are obvious. In Dallas, coach Mike McCarthy’s contract is ending. He has done nothing this year that would merit a new one.

The Jaguars have woefully underperformed, especially after owner Shad Khan said in August that it’s the best Jacksonville team ever assembled. And the Raiders and Bears have made significant in-season changes that could be a stopover toward a cleaning house after the season, if not sooner.

Giants owner John Mara has said he doesn’t anticipate making any changes after the season. Changes could nevertheless be made.

If the Buccaneers continue to underperform, could Todd Bowles be in trouble? Maybe, if ownership thinks it can lure Bill Belichick to town, five years after Tom Brady went to Tampa.

If the Colts don’t make it to the playoffs, what will Jim Irsay do?

Then there’s the ever-present possibility for a surprise. Could Dolphins owner Stephen Ross, who declared the team to be Super Bowl ready before the season, clean house if they miss the playoffs — even with coach Mike McDaniel getting an extension in the offseason? Could Brian Callahan be one and done in Tennessee? Jerod Mayo in New England?

Then there’s always the possibility of a resignation or retirement.

Last year, there were eight vacancies — 25 percent of the entire league. This year, there could be another eight openings.

Whatever the number, it’ll always happen. It’s the quickest way for a bad team to become a good team, especially since the salary cap restricts what a team can do to improve.