UPDATE 1-NFL-Marrone quits as head coach of Buffalo Bills

* Marrone opts out of contract * Guided Bills to first winning season in a decade (Adds detail) Dec 31 (Reuters) - Doug Marrone has resigned as head coach of the Buffalo Bills, the National Football League (NFL) team announced on Wednesday. Marrone departs just three days after guiding the Bills to their first winning season in a decade. They finished 9-7. He leaves after serving two years of his contract. According to media reports, Marrone had an option in his deal that gave him until the end of Wednesday to opt out, and he will get a $4 million payout. "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," Buffalo owner Terry Pegula said in a statement. "We are disappointed that (he) will no longer be an important part of our organization. "We will now begin the important process of conducting a thorough search for a new head coach as we continue to strive to reach our goal of returning to the playoffs and bringing a championship to Buffalo for our fans." Marrone's departure means that at least five NFL teams will have new head coaches next year. The Chicago Bears, Atlanta Falcons and New York Jets dumped their coaches on Monday, while Jim Harbaugh left San Francisco by "mutual" agreement to take the helm at the University of Michigan. Marrone, 50, took his first NFL head coaching position with Buffalo after four seasons in charge at Syracuse University where he finished with a 25-25 record. The Bills went 6-10 in his first season in charge in 2013, before improving substantially this year and almost making the playoffs. (Reporting by Andrew Both in Cary, North Carolina; Editing by Mark Lamport-Stokes)