It's Week 13 in the NFL and that means the term "mathematically eliminated" starts entering the football lexicon. Teams like Philadelphia and San Diego, both with 4-7 records and sitting at or near the bottom of their respective divisions, are still in the playoff hunt thanks to numbers and calculations. In other words, they haven't been mathematically eliminated from playoff contention, but there's little chance in hell they'll make the post-season.

The reality is that as competitive as the NFL is, the season is just about over for close to half of the league's 32 teams. And for some of those franchises, that means time to clean house.

The re-organising and restructuring has already started in the AFC South, with Jacksonville firing longtime coach Jack Del Rio and winless Indianapolis sacking defensive coordinator Larry Coyer.

Del Rio, only the second coach in Jaguars' history, had a 68-71 record overall, but the team hasn't made the playoffs since 2007. Most believed this season was Del Rio's last chance to save his job, but a 3-8 record and the slow development of rookie quarterback Blaine Gabbert has forced owner Wayne Weaver's hand. Ironically, Weaver also announced that he's selling the Jaguars, so this now becomes the problem of the new owner, auto magnate Shahid Khan.

Indianapolis, which has played without superstar Peyton Manning all year, is 0-11 and will surely make more moves once the season ends. Firing Coyer is more symbolic and perhaps one that can motivate the defense in the last few weeks of the season. It's also a desperate maneuver by head coach Jim Caldwell to save his own head. Caldwell has a 26-20 record in three seasons with the Colts, but this year's debacle - even without Manning - has increased the pressure.

These won't be the only sackings of 2011. Here are a few other coaches on the "Hot Seat":

Andy Reid, Philadelphia (4-7): Reid has had his ups and downs over the years and is one of the NFL's more controversial coaches. He's stubborn and his clock management skills are deplorable. But his career record is 132-89-1 and he's taken the Eagles to five NFC championship games and one Super Bowl.

Keep him because: His record speaks for itself.

Sack him because: The so-called "Dream Team" has been a disaster.

Mike Shanahan, Washington (4-7): In his second year with the Redskins, Shanahan is trying to avoid another last place finish in the NFC East. Shanahan has the support of owner Dan Snyder, but some of his personnel decisions have been questionable. His insistence on the quarterback combination of Rex Grossman and John Beck hasn't really paid off, and his puzzling use (or non use) of various running backs has frustrated the fanbase.

Keep him because: It's only his second year and there have been some positive signs.

Sack him because: Shanahan is unlikely to recapture the magic he had with two Super Bowl winners in Denver.

Tony Sparano, Miami (3-8): Has really managed to get his Dolphins playing hard for him in the past few weeks, but there are real questions about which way the club is heading. His record at Miami is 28-31, but he was 11-5 in his first season. Since then it's been 7-9, 7-9 and this year, 3-8. The Dolphins are also terrible at home, having won only three games in two years in front of the Miami faithful.

Keep him because: Few losing teams have played with the spark and effort that Miami has.

Sack him because: The franchise needs to take a step in the right direction.

Norv Turner, San Diego (4-7): No coach in the NFL has done as little with as much as Turner. The Chargers have been tipped to go far in the post-season for the past three or four years. Last year they failed to make the playoffs. This year, they're 4-7 and mired in a six-game losing streak. There's no doubt Turner is a brilliant offensive mind, but his head coaching has been a litany of foolish mistakes, sloppy game management and poor personnel decisions.

Keep him because: General Manager A. J. Smith deserves as much blame as Turner, and perhaps there's a scenario where Smith takes all the blame.

Sack him because: It's time for a change: no team has been a bigger underachiever.

College firings

Meanwhile in college football, the season is literally over for many teams, and with no bowl game to be played, most of those head coaches are facing some scrutiny, if not the axe.

The Pac 12 conference is leading the way in the firing stakes, with four sackings already. Arizona parted company with Mike Stoops a few weeks ago, while cross-state rival Arizona State canned Dennis Erickson after a sub-par season. Washington State officials agonised, but finally decided to say goodbye to Paul Wulff, while former Colorado and Washington coach Rick Neuheisel has been fired by UCLA. Interestingly, Neuheisel will coach this week; in his final game, the Bruins will be 31-point underdogs against Oregon.

Other sackings included Ron Zook (Illinois), Turner Gill (Kansas), Larry Porter (Memphis), Neil Callaway (UAB) and Rob Ianello (Akron). Ole Miss head coach Houston Nutt resigned earlier in the season and in the biggest news of all, Ohio State's interim head coach Luke Fickell was moved on to make way for Urban Meyer, who won two national titles at Florida.