The award for most bizarre NFL offseason definitely goes to the Buffalo Bills.

One day after the season ended, starting quarterback Kyle Orton announced his retirement. Shockingly, that was only the second most surprising think to happen in Buffalo this week thanks to Doug Marrone.

The Bills coach opted out of his contract on Wednesday, meaning he's free to sign with any team.

"Doug Marrone informed me late today that he has decided to exercise the option clause in his contract and relinquish his responsibilities as our head coach," Bills owner Terry Pegula said in a statement. 

Here are five things you need to know about Marrone leaving

1. What is an opt-out clause and why did Marrone have one? An opt-out clause is exactly what it sounds like: It's a clause that gives a coach the chance to option out of his contract early. Most coaches don't have opt-out clauses in their contract, but Marrone had one because of the tenuous ownership situation in Buffalo -- related to Ralph Wilson's health -- that was going on when he was hired in January 2013. 

The opt-out clause was only to go into effect if the Bills changed ownership while Marrone was still the coach. After Bills owner Ralph Wilson died in March, the team was put up for sale and eventually sold to the Pegula family. The Pegula's purchase of the team was finalized in October. 

The ownership change triggered a three-day out clause for Marrone, meaning that once the regular season ended, he had three days to opt-out. The clause was set to expire on Wednesday night. 

Doug Marrone is out in Buffalo. (USATSI)
Doug Marrone is out in Buffalo. (USATSI)

2. Why did Marrone opt-out? There's a lot of reasons why Marrone might have opted out. CBS Sports NFL Insider Jason La Canfora reported on Wednesday that Marrone wasn't getting along with Bills general manager Doug Whaley. 

It might not just be Whaley though, the Bills have several other problems. Buffalo has no first-round pick in the 2015 draft, they kind of don't have a quarterback and there's no guarantee that Pegula would keep Marrone beyond 2015. According to the Buffalo News, Marrone asked for a contract extension, but was told no.

That might have been enough to send him packing.

There's also the possibility that Marrone opted out of his contract because there's another job he wants, which takes us to our next subject. 

3. What's next for Marrone? The Jets don't have a coach, Marrone is from the Bronx and he coached New York's offensive line from 2002-05. What I'm trying to say is, there's a good chance Marrone ends up in New York. 

As pointed out by NFL.com, the Jets have interviewed a minority candidate and fulfilled the Rooney Rule, which means they could hire Marrone before the new year hits if they wanted to. 

4. What's next for Buffalo? La Canfora reports that Chargers offensive coordinator Frank Reich will likely emerge quickly as the main candidate in Buffalo. Reich, who was the Bills backup quarterback from 1985-94, just finished his first season as an NFL coordinator. 

Whomever gets the job will inherit a team that went 9-7 in 2014, the Bills first winning record since 2004. The new coach will also inherit a defense that finished fourth overall in the NFL in 2014. 

Another coaching possibility could be the man that directed the Bills fourth ranked defense: Defensive coordinator Jim Schwartz. Schwartz coached the Lions for five seasons before being fired in 2013. Marrone hired Schwartz to be his defensive coordinator in January 2014. 

5. We might have to make Marrone's nickname 'Money.' The craziest part of Marrone's opt-out clause is that the Bills have to pay him $4 million in 2015 -- no matter what. There was no offset clause in the contract, so if Marrone gets hired by another team, he'll make his new salary plus his salary from the Bills. 

If there had been an offset clause, the Bills wouldn't have had to pay Marrone any money that another team was paying him. So if Marrone was paid $1 million next season by another team, then the Bills would only owe him $3 million, instead of the $4 million.

That's not the case though and Marrone will receive his entire 2015 salary from the Bills, even if he's coaching somewhere else in 2015.