Is John Fox the coach of the year?

The easy money is on Jim Harbaugh. No one thought that a college coach, even one with an NFL background, could step into a franchise that hadn't been to the playoffs in nearly a decade and turn it around in a matter of months without the benefit of an offseason.

It is ridiculous, really, what Harbaugh has been able to do for San Francisco. At 9-2, the 49ers have the second-best record in the NFL and the league's best defense. They've allowed only 15 touchdowns, are first in red zone defense and have made it so that Alex Smith, who is having his best season in seven years as a pro, doesn't have to win games with his arm.

So, yes, the rookie coach, whose team can clinch a playoff berth Sunday with a win over St. Louis, probably will win the Coach of the Year award. Mike McCarthy will push Harbaugh, whether the Packers finish perfect or not. So will Gary Kubiak or Lovie Smith, if either can hold his team together despite losing his starting quarterback to injury. If the Bengals somehow win the AFC North, Marvin Lewis will be in the debate.

But if the Denver Broncos win the AFC West, or even if they make the playoffs as a wild card, John Fox should be Coach of the Year. In his first season with the Broncos, Fox has rebuilt the defense, switching from a 3-4 to a 4-3, and made a radical midseason shift, benching quarterback Kyle Orton for Tim Tebow and an option-heavy offense. It probably won't work forever -- this is a passing league, after all -- but Tebow is working right now.

Fox doesn't want the credit, but he deserves it.

Even if the intention of switching to Tebow during the bye week, when the Broncos were 1-4, was to let Tebow demonstrate why he is not a legitimate starting quarterback, it doesn't matter. Like the rest of the Broncos, Fox seems to be all-in on Tebow.

Denver is 5-1 with Tebow as the starter. The Broncos have vaulted from tied for 25th in rushing through the first four weeks of the season, averaging 86.8 yards per game, to No. 1 in the league, averaging 159.7 yards per game. In the past seven games, six of which Tebow started, they have averaged 201.4 rushing yards.

Although young, the offensive line has benefited from having all five starters -- Ryan Clady, Zane Beadles, J.D. Walton, Chris Kuper and Orlando Franklin -- play every game. Willis McGahee, one of the Broncos' offseason acquisitions, has gone from a situational rusher to a back with five 100-yard games, second-most in the NFL.

And Tebow has been unstoppable with the ball in his hands and the game on the line. Fox has lived by the newfound philosophy of keeping a game close and letting Tebow win it in the end.

The Broncos have been within three points entering the fourth quarter of the past four games -- and won. Before getting blown out by Detroit, they trailed Miami by 15 points with three minutes left and won in overtime. They beat Oakland by 14, Kansas City by seven, the Jets by four and San Diego by three, again in overtime.

It is working. Fox is making it work.

Fox's defense doesn't get enough of the credit, but it has made Tebow's success possible. In the past four games, the Broncos' D has allowed opponents to convert on only 27.8 percent of their third downs. Detroit holds the season lead in that category at 28.0 percent, and the league average is 38.2.

Denver has been particularly good in the fourth quarter of the past four games, giving up only six points and allowing three third-down conversions.

Von Miller probably will win Defensive Rookie of the Year. He leads the AFC and is tied for third in the NFL with 10.5 sacks, and he has 4.5 in his past four games. A year after tearing his pectoral muscle during training camp, Elvis Dumervil has 5.5 sacks.

The secondary, which was decimated by injuries in 2010, has been solid. Veterans Champ Bailey and Brian Dawkins, now in his 16th season as a safety, are playing well despite their age.

Fox seems to have fixed the defense in less than a year without an offseason. The past four games are proof.

Who knows how long the Tebow train will keep rolling, but it is clear that the players have bought in. A move such as this could have fractured a team. Instead, it gave the Broncos a purpose.

Denver trails the 7-4 Raiders by one game but has the easier schedule. The Broncos will play at Minnesota on Sunday, then get Chicago without Jay Cutler, New England at home, are at Buffalo and host Kansas City. Oakland will play at Miami and Green Bay, Detroit at home, at Kansas City and San Diego at home.

The Raiders and Broncos split the season series, each winning on the other's field.

Fox was asked this week to define the identity of his team. In not really answering the question, Fox illuminated just how difficult a task he has faced turning the Broncos around.

"There is no manual on it," he said. "I [had] been somewhere so long that I knew the team, knew what they were capable of. The tough part of coming here was that we had no offseason, so you didn't even get to walk through the weight room and watch how they worked in the weight room or in the conditioning program. That's something I've mentioned earlier; it's not X's and O's and schemes and all that. It's just knowing guys' makeup, knowing what buttons to push, know how they react, what kind of competitors they are. When you don't have any competitive situations, those things are hard to figure out.

"I think there were some growing pains with that early. I'm not just talking about with me. I'm talking about the whole staff. I think we're just getting more familiar with each other."

Harbaugh has excelled at molding his team, but given the degree of difficulty of a midseason change in quarterback and offensive philosophy, if the Broncos continue this run into the playoffs, Fox should be Coach of the Year.

Ashley Fox covers the NFL for ESPN.com.