Associated Press

Gary Kubiak is out in Houston, the first NFL coach relieved of his duties. With three weeks remaining in the regular season, from North (Leslie Frazier) to South (Mike Munchak), from East (Mike Shanahan) to West (Dennis Allen), there are plenty more candidates to get canned.

Also potentially on the firing line: Rex Ryan in New York, Greg Schiano in Tampa Bay, and Mike Smith in Atlanta.

A coach's shelf life in the NFL depends on far too many factors for them to ever truly feel secure. Indeed, only Bill Belichick in New England, Marvin Lewis in Cincinnati and Tom Coughlin in New York have held their jobs since 2004.

Injuries, changes in upper management or ownership, free agency, the draft -- they all contribute to success and failure. Coaches have no control over the first two and might have limited input for the other two.

The record rarely matches expectations of the people who own teams, which is when patience is required most. When a team totally collapses and becomes an embarrassment to the franchise, as the Texans have done in 2013, there's little choice what to do.

Here's which coaches on the hot seat figure to have done enough to remain acceptable to their bosses, and which ones likely will be looking for work in 2014.

On the Precipice

Everything in the nation's capital indicates Mike Shanahan is a goner. He's been heavily criticized for the handling of Robert Griffin III in last season's playoff game; for his use of RG3 as the quarterback was coming off a knee injury sustained in that game; for a passing offense that has lost its way; and for a defense that has lost all mojo in Washington (3-10). The Redskins have the worst special teams in the NFL under a coordinator hand-picked by Shanahan this season from his old Denver days.

That Shanahan and Griffin have publicly clashed this year, along with this week's benching of RG3, doesn't help the two-time Super Bowl winner's case with an owner known for his impatience.

Frazier also is on slippery turf. The Vikings (3-9-1) do play hard, if not very well, and without the sensational Adrian Peterson in their backfield, they would be even closer to earning that top overall draft pick. In-game strategy has been shaky, particularly in tight games. The defense this year has been awful, especially at the end of games, losing a late-fourth-quarter lead five times and going 0-4-1 in those.

Approaching the edge

Munchak pretty much was handed an ultimatum in his third season in charge to get into the playoffs. That won't happen, but he did lose his quarterback, Jake Locker, for a big chunk of the season.

Owner Bud Adams died in October, and leadership has fallen to his son-in-law. The family almost certainly would like to keep Munchak -- Adams' relatives asked Mun chak to give the eulogy at the memorial service. But if the Titans (5-8) go 5-11 in a very weak AFC South, keeping the Hall of Famer (as a guard) could be too difficult to explain.

Allen's second year in Oak land hasn't been much better than his first, but he walked into a salary cap mess with the Silver and Black. He's gotten nice production out of some second-stringers while injuries have ravaged the starting lineup.

He's also gotten performances from the Raiders (4-9) like last Sunday's debacle at the Jets, or a 49-20 flop against Philly.

Al Davis never brought back a coach after consecutive full losing seasons. How will son Mark react?