Patriots offensive coordinator Josh McDaniels, left, is one of the hottest candidates for a number of head coaching vacancies. Reuters

As 12 NFL teams prepare for the playoffs, the 20 remaining franchises are licking their wounds and formulating plans for next season. Of that 20, six are currently starting a major overhaul of their coaching staff with the most pressing need being the head coach: the Buffalo Bills, Denver Broncos, Jacksonville Jaguars, Los Angeles Rams, San Diego Chargers and San Francisco 49ers.

Each team, with the exception of Denver, fired their head coaches and are now scouring the professional and college ranks for their next leader. Gary Kubiak reportedly stepped down in Denver for health reasons, less than a year removed from leading the Broncos to their third Super Bowl title.

The other coaches who were fired didn’t have nearly as much success. Buffalo booted Rex Ryan, Jacksonville let go of Gus Bradley, the Rams finally parted ways with Jeff Fisher, the Chargers dismissed Mike McCoy and the 49ers cut short an experiment with Chip Kelly. Each coach was unable to lead their team to the postseason or consistently win games at the highest level.

There have been rumblings that two more spots could open up. The Indianapolis Colts have toyed with the idea of firing Chuck Pagano, and the Houston Texans and Bill O’Brien could be on the outs despite making the playoffs, FOX’s Jay Glazer reported Sunday.

Buffalo Bills

Interim head coach and former offensive coordinator Anthony Lynn took over following Ryan’s firing after Week 16, and he appears to be the frontrunner with star running back LeSean McCoy recently telling reporters that Lynn is the kind of coach “we need.” But there is competition for Lynn, with ESPN reporting the Rams formally requested to speak to Lynn and NFL Network also reporting the 49ers also wish to speak to him. Lynn’s expected to meet with both teams, while the Bills have also reportedly asked to interview Arizona Cardinals offensive coordinator Harold Goodwin and Carolina Panthers defensive coordinator Sean McDermott.

Denver Broncos

The daily mental pounding of an NFL season became too much for Kubiak. So, the Broncos are now kick-starting their second head coach search in two years and it may start from the same place as last time. NFL Network said Denver nearly hired current Miami Dolphins defensive coordinator Vance Joseph and he could available again this time around. But Denver is also looking elsewhere, with general manager John Elway saying Monday he had an idea of three or four potential candidates, according to the Denver Post. The report says current Atlanta Falcons offensive coordinator Kyle Shanahan was asked to interview, while the Rams, Jaguars and 49ers have also requested meetings. Kyle Shanahan's father, Mike Shanahan, coached Elway and the Broncos to Super Bowl titles in 1998 and 1998.

Jacksonville Jaguars

After the Jags sputtered along under Bradley, they have turned their attention to former Atlanta head coach and current Tampa Bay defensive coordinator Mike Smith, the Tampa Bay Times reported Monday. Smith’s candidacy comes on the heels of an interview last week with former Giants head coach Tom Coughlin, ESPN reported. Coughlin, 70, served as the Jaguars' first head coach and guided the club to four straight postseason appearances.

Los Angeles Rams

The Rams have eagerly pursued some of the most notable assistants throughout the NFL. New England offensive coordinator and former Denver head coach Josh McDaniels was already brought in, as has Shanahan. Goodwin, Lynn and Joseph have also received interest from Los Angeles. Meanwhile, Washington offensive coordinator Sean McVay and Carolina defensive backs coach and assistant coach Steve Wilks are also expected to be in the running.

San Diego Chargers

Many Chargers were upset with McCoy’s dismissal, but management is moving on after failing to make the postseason once again. ESPN reports that Patriots defensive coordinator Matt Patricia was asked to formally interview and will have to take place while New England’s on its postseason bye. A big question for any prospective head coach will be if the Chargers will be playing in San Diego or Los Angeles next season.

San Francisco 49ers

The 49ers are in pursuit of a new GM and a new head coach. San Francisco will reportedly first hire a GM, who will then be responsible for hiring a head coach. There are reports that former Chiefs GM Scott Pioli and ex-NFL personnel executive Louis Riddick may be in line for GM, while Joseph, McDaniels, Lynn and Shanahan are all possibilities to be the next head coach.