Just as people in the retail industry are all too familiar with Black Friday, people in the sports industry -- particularly the NFL -- are all too familiar with Black Monday.

Sunday marked the final day of the NFL's 2013 regular season and a number of disappointing teams have already started cleaning house. At least six teams have made firings since the end of Week 17.

Heading into the week, the Washington Redskins were expected to make a decision on the future of head coach Mike Shanahan and they did not waste any time. Speculation turned into reality on Monday when Shanahan was officially fired.

Another coach that was on the hot seat for a much longer time -- Bucs coach Greg Schiano -- also got canned. Schiano had a disastrous tenure in Tampa Bay after he was brought in from Rutgers University in 2012.

Minnesota was a third team to fire its head coach on Monday after reports emerged about Leslie Frazer. According to ESPN.com, sources told Adam Schefter that Jack Del Rio and Adam Gase of the Denver Broncos were top priorities as replacements.

Among other teams to fire its coach included the Cleveland Browns. The team was quick to pull the plug on Rob Chudzinski's tenure as coach. Chudzinski was only one year into his tenure with the team and he will now be owed $10.5 million. The Browns struggled mightily in the second half of the season en route to a 4-12 mark.

The organization released a statement about the firing.

"We appreciate Chud's passion for the Browns, and we have great respect for him both personally and professionally. We needed to see progress with this football team. We needed to see development and improvement as the season evolved and, unfortunately, we took a concerning step backward in the second half of the year," the statement read.

"Our fans deserve to see a consistently competitive team. We have high standards, and there's an urgency for success. When we believed we were not positioned to achieve significant progress in 2014, we knew we had to admit that a change was needed, and move forward."

What do you think about these firings? Were they justified? Should any other coaches get fired too? Let us know in the comments section!