Three NFL coaches lost their job on a day known as 'Black Monday' as a result of its history of sackings.
Tom Coughlin, who won two Super Bowls with the New York Giants, stepped down after failing to make the play-offs for the fourth successive season.
The San Francisco 49ers dismissed Jim Tomsula, 47, after only a year in charge as they slumped to a 5-11 record to finish bottom of the NFC West.
The Cleveland Browns split with coach Mike Pettine and manager Ray Farmer.
Pettine, 49, coached the Browns for under a year and their 3-13 record saw them finish bottom of the AFC North.
Since the latest success, a dramatic 21-17 victory over the New England Patriots, the Giants' fortunes have steadily worsened and they ended the last two campaigns with a 6-10 record.
Tomsula was a surprise appointment by the 49ers when he was promoted from defensive line coach, his only head coach experience at professional level being in NFL Europe with Rhein Fire.
The 49ers were the dominant team in the 1980s and early '90s under the guidance of Bill Walsh and then George Seifert but they have not won a Super Bowl since their fifth success in 1994.
The play-off picture
The NFL's regular season closed on Sunday with 12 teams qualifying for the play-offs.
Eight teams must contest a wildcard round on the weekend of 9 and 10 January, with the four winners progressing to meet the four franchises already through to the next round by virtue of their performances during the regular season.
The New England Patriots - winners of last year's Super Bowl - are one of those teams already through, despite being beaten to top-seed status in the AFC by 2014 finalists the Denver Broncos.
The Broncos saw off San Diego 27-20 in their final regular-season game and will hope to reach their second Super Bowl in three years, having lost heavily to Seattle Seahawks in 2014.
The Washington Redskins go into the play-offs with four straight wins.
This year's showpiece final - Super Bowl 50 - will be played on 7 February at Levi's Stadium in California, current home of the 49ers.
The play-off fixtures
Saturday, 9 January (seeds in brackets)
Kansas City (5) at Houston (4) - 16:35 Eastern Time (21:35 GMT)
Pittsburgh (6) at Cincinnati (3) - 20:15 Eastern Time (01:15 GMT)
Denver Broncos to face the lowest seeds remaining in next round, New England Patriots to meet highest seeds remaining.
Sunday, 10 January
Seattle (6) at Minnesota (3) - 13:05 Eastern Time (18:05 GMT)
Green Bay (5) at Washington (4) - 16:40 Eastern Time (21:40 GMT)
Carolina Panthers to face the lowest seeds remaining in next round, Arizona Cardinals to face the highest seeds remaining.
Giants coming to Twickenham
Despite their poor recent form, the New York Giants remain one of the NFL's biggest draws - and they will make history in Britain later this year.
When the 2016 regular season begins, the four-time Super Bowl winners will play a match in London for the first time since 2007 when they take on the St Louis Rams in the first NFL game to be played at Twickenham, the home of English rugby union.
The fixture - on 23 October - will be one of three in the UK in 2016 as the Indianapolis Colts versus the Jacksonville Jaguars and the Washington Redskins against the Cincinnati Bengals will take place at Wembley.