INDIANAPOLIS (AP) — Bruce Arians feels like he's living out a fantasy.

After two decades as an NFL assistant and less than 12 months after being forced out as Pittsburgh's offensive coordinator, the Colts interim coach has delivered a memorable performance in his first — and perhaps only — role as an NFL team's leading man.

He's won eight games since replacing the Chuck Pagano, who is recovering from leukemia. Incredibly, Arians has Indianapolis on the verge of making the playoffs. He's guided Andrew Luck through a record-setting rookie season, has the offense clicking, the usually maligned defense believing and a forgotten special teams unit making big plays. He's even getting mentioned as a coach of the year candidate, an award no interim coach has ever won.

Within two weeks, this made-for-Hollywood script could change again when Arians gladly hands the head coaching duties back to Pagano.

"I'll get more sleep," Arians joked Wednesday before turning serious. "Look, it's been fun, and I would be lying if I said it hasn't. But the whole goal was to keep it together until Chuck came back."

Arians has done more than keep these Colts (9-4) unified, he's given them purpose and direction by keeping Pagano and his battle with leukemia in the forefront. It's true that screenwriters couldn't have conjured up more plot twists than the feature attraction in Indianapolis. This is part "Brian's Song," part "Hoosiers."

From the moment he spoke with Pagano on Sept. 30, Arians had 21 hours to adjust to the idea he was no longer just Indy's offensive coordinator. He also needed a plan to be the interim coach. It didn't take long for Arians to figure out what he needed to do.

As a prostate cancer survivor, Arians has been able to explain the challenge Pagano faced on Sept. 26 and the day-to-day grind he's had since then.

As one of pro football's top tutors of young quarterbacks, Arians refused to sacrifice precious time helping Luck, carving out extra hours to meet face to face with his star rookie.

A humble man with a simple approach to life, Arians won over the veterans with substance, kept the roughly three-dozen newcomers grounded enough to focus on football, and never let these players lose sight of their overall mission: playing well until Pagano got back on the sideline. The target date for Pagano's return is Dec. 30, Indy's regular-season finale, and a game that could decide the AFC South title.

Outsiders aren't the only ones raving about Arians' performance.

Linebacker Robert Mathis, a converted Pro Bowl defensive end, calls Arians the team's MVP. Four-time Super Bowl-winning kicker Adam Vinatieri credits Arians with providing a season's worth of mental and spiritual inspiration. Luck appreciates that Arians held nothing back in training camp and never let their communication diminish even when the coaching circumstances changed.

Those who know Arians as a longtime head coaching understudy are not surprised the Colts are 9-4 and need just one more win to clinch a playoff spot.

"I think he's been successful because he's really stayed true to some basic principles," first-year general manager Ryan Grigson said. "Every week, he reminds the team that we are playing for our fallen leader, and he had the courage and the belief when almost nobody else did to say that we were going to extend this season so Chuck could come back. Despite getting our butts whipped on the road, beating Green Bay, pulling out any number of victories we've had, he's held it together. But he feels like we've done nothing yet, and he means it."

Actually, Arians has done more than he thinks.

He's helped Luck break NFL rookie records for 300-yard games (six), fourth-quarter comebacks (six) and has him within 259 yards of Cam Newton's record for yards passing (4,051). Luck also has more wins than any quarterback selected No. 1 overall since the 1970 AFL-NFL merger.

Despite having 21 players on the roster with one season or less of NFL experience, the Colts have won a league-high eight one-possession games and have seven more wins than they did in 2011. With wins in the last three games, Indy would earn only its second division title without Peyton Manning since moving from Baltimore. It would get a home playoff game and tie the NFL record for biggest one-season turnaround (10 more wins). The Colts set the mark in 1999 with Manning. Miami matched it in 2008.

Arians also needs one more win to tie the NFL record for victories following a midseason coaching change. According to STATS LLC, he's currently tied with Don Coryell (eight, 1978 San Diego Chargers) and trails only Wally Lemm (1961 Houston Oilers) and Hamp Pool (1952 Los Angeles Rams), who won nine games.

"It's not just what he's done in terms of wins and losses," Vinatieri said. "To come in here with a new GM, a new head coach, new players and be the guy is a pretty doggone good job in and of itself. To do it under these circumstances, is remarkable. I don't have a vote, but I definitely think he deserves to be coach of the year."

But until now, Arians has never called all of his own shots. This season could change everything.

His resume is strong:

—Two Super Bowl rings and three Super Bowl appearances with the Pittsburgh Steelers.

—Mentor to Pro Bowl quarterbacks Manning and Roethlisberger, and now Luck.

—Assisted with two of the biggest one-year turnarounds in league history.

—Architect of the first NFL team with a 4,000-yard quarterback, two 1,000-yard receivers and a 1,000-yard runner.

—Head coach for six seasons at Temple and, of course, almost one full season as the Colts' interim coach.

"He's a player's coach. I talked to some of the other Colts players and they really enjoy playing for him. They respect him," Roethlisberger said. "They've got something special going on over there. It's really neat to see with Coach Pagano and all of the stuff they're going through."

Will another team take a chance on a 60-year-old who might not be a perfect fit in the image-conscious NFL world?

"If something opens up down the road, I would love it," he said. "If not, I love it here."

Even as he and the Colts are preparing for perhaps the strangest twist of all: making another coaching change just as the playoffs begin.

"We'll just go back to the same role we had before," he said.

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AP Sports Writer Will Graves in Pittsburgh contributed to this story.