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By MICHAEL MAROT

AP Sports Writer

INDIANAPOLIS (AP) - Bruce Arians always wanted to coach his own NFL team.

The chance has arrived, and not how he wanted it to go. He will be replacing an old friend on an interim basis in the middle of a season because of a serious illness. The longtime NFL offensive coordinator has no illusions about the job as he tries to help the Colts get better while everyone hopes coach Chuck Pagano returns soon from leukemia treatments.

This isn't a head coaching job for me right now,'' Arians said after being named Indy's interim coach Monday.It's just an expanded role as coordinator until Chuck comes back.''

Arians was an obvious choice.

The Colts' front office followed Pagano's advice and hired Arians, an assistant who had coached with or against Pagano for the better part of a decade. He's someone who mentored three quarterbacks selected No. 1 overall (Peyton Manning, Tim Couch and now Andrew Luck) and has the same kind of personality that hooked the Colts on Pagano.

Team owner Jim Irsay and new general manager Ryan Grigson also liked his previous experience in Indy and his resume.

Arians also played a key role in the development of Pittsburgh quarterback Ben Roethlisberger and won two Super Bowl rings with the Steelers - one as the receivers coach, the other as offensive coordinator - before his forced retirement earlier this year. He spent two seasons as Paul ``Bear'' Bryant's running backs coach at Alabama and six seasons as Temple's head coach.

He's a veteran. He knows this game well. He has a great synergy with the staff and with Chuck,'' Grigson said.He's going to be able to bridge that gap between Chuck and himself and this team because they (the assistants) have a brotherhood on that staff like I've never seen. Chuck's our brother, and we are all here for him. Bruce is the man to lead us forward while our leader is down.''

Arians understands this peculiar predicament better than most.

In two decades as an NFL assistant, Arians has seen and done just about everything. And five years ago, Arians was the one being diagnosed with cancer. He needed a radical prostatectomy just before the NFL draft.

That phone call is not a fun one,'' Arians recalled.I was sitting in my office and they kept telling me there's nothing wrong, nothing wrong and then the doctor calls and tell you you've got cancer. You really don't remember the next 24 hours. ... I'll tell you I could hardly drive home. It's devastating to get that message. Then you figure out, like we always do, what's the plan.''

The plan in Indy is to let Arians call the shots temporarily.

Players universally approve.

Coach Arians and I spoke briefly about making sure the communication is not lost, so I don't think it will be,'' Luck said.He's seen everything in the world of football, so I'm sure he'll do a great job and still manage to keep his (finger on the) pulse of everything the offense is doing.''

Arians intends to keep calling plays, as he had planned to do if ever got that elusive head-coaching gig.

Indy's defense is embracing the choice, too.

During the first practice without Pagano, players were surprised to see just how quickly - and smoothly - Arians could adapt to his new duties. And though it sounded strange coming from the mouth of a longtime offensive guy, Arians wasted no time in praising the defense for forcing a couple of late turnovers.

It was odd, awkward,'' outside linebacker Robert Mathis said, drawing laughter.We like to have fun during practice and he likes to talk trash to us, so to see him cheering for us, it was a little different.''

How long Arians will be pulling double duty isn't clear.

Pagano was admitted to an Indianapolis hospital last Wednesday to begin treatment. Dr. Larry Cripe, Pagano's physician, said the coach will be treated with chemotherapy and drugs - a process that usually requires patients to spend four to five weeks in the hospital. Irsay said he expected Pagano to stay a bit longer, six to eight weeks, and does not anticipate Pagano taking over his full head-coaching duties the rest of this season.

If Pagano doesn't make it back to the sideline before the Dec. 30 regular-season finale, Arians has given the Colts (1-2) another goal.

``Why can't we extend the season so he can come back?'' Arians said.

Indy's playoff quest restarts Sunday when the Packers (2-2) visit Lucas Oil Stadium - a day that Arians will lead the Colts onto the field for the first time. And although it's something Arians has always dreamed of doing, it will be a day and a season filled with concern for his longtime friend.

His family is my family,'' Arians said.When he made the call to me to come, there was never a doubt or a hesitance on my part because I knew he would do this right, and he's doing it the right way. We're just going to continue that until he gets back.''