INDIANAPOLIS (AP) Three years ago, Andrew Luck walked off the field in Chicago and promised to learn from a forgettable NFL debut.

The Colts rookie had just thrown three interceptions, one touchdown pass and barely completed half of his 45 throws in a 41-21 loss to the Bears.

He's come a long way since. On Saturday, Luck will be back on his home turf ready to face Chicago again - this time as the presumed standard bearer for the next generation of NFL quarterbacks.

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''I would like to think I have grown mentally, emotionally, physically. I think I have a better understanding of what it means to be an NFL quarterback,'' Luck said Thursday before Indianapolis' second practice against the Bears.

Whatever the explanation, the Colts and Bears - and their two quarterbacks - have gone in drastically different directions since the 2012 season opener.

Back then, Luck was viewed as the young gun, running an offense in rebuild mode. Indianapolis wasn't even supposed to be a playoff contender.

Bears fans, in contrast, viewed Jay Cutler as their long-term answer at quarterback, someone who could finally turn the Bears from a solid playoff team into a legitimate title contender.

Instead, Indy's stability wound up paying big dividends.

Luck has led the Colts to three consecutive 11-win seasons, back-to-back division titles, an AFC championship game, and perhaps now the role of biggest threat to dethrone Super Bowl champion New England.

The secret of Luck's success is no secret.

''Sometimes it's hard for guys to take constructive criticism. I think Andrew takes it very well,'' backup quarterback Matt Hasselbeck said. ''If you tell him something, he'll write it down, say `Thank you very much,' and he works on it.''

Hasselbeck also has seen enough in his 17-year career to understand that a good, smart quarterback doesn't win games by himself. The decline of Cutler, who played high school football in southern Indiana, is a perfect example.

While Luck enters his third season under offensive coordinator Pep Hamilton and his fourth with head coach Chuck Pagano, Cutler has played for three head coaches and five offensive coordinators since joining the Bears in 2009.

This year, Cutler's favorite receiver, Brandon Marshall, was dealt to the Jets, and now the Bears' projected starting receivers, Alshon Jeffery and Kevin White, are both hurt. Jeffery missed both practices in Indy this week with a strained calf. White is expected to miss a large part of the season after undergoing surgery on his shin.

Without them, Cutler acknowledged the Colts' starting defense outplayed the Bears' No. 1 offense on Wednesday, and it may not get much better Saturday.

''I would like to work with Alshon and Kevin, but it is what it is,'' Cutler said Wednesday. ''We're shifting some guys in there, some guys are getting some work with the ones, and some of the threes are getting work with the twos, so it's a good thing we're seeing everybody right now.''

Cutler also is to blame for Chicago's struggles.

His 44 turnovers over the past three seasons rank fourth in the NFL, just ahead of Luck at 43, according to STATS. And while Cutler has completed a higher percentage of passes than Luck (62.9 percent to 58.6) and thrown for nearly as many yards per attempt as his counterpart (7.0 to 7.1), Luck has thrown 20 more TD passes and won 36 games, including three in the playoffs.

Cutler is 20-21 over that span and hasn't appeared in the postseason since Chicago's NFC championship game loss to Green Bay in January 2011.

There's one other problem: The Bears' once feared defense allowed the two highest point totals in franchise history in 2013 and 2014, forcing Cutler to play catch-up much of the time.

That's not a winning recipe for any quarterback.

Meanwhile, the Colts understand they're fortunate to have gotten Luck, who has made people forget about those bad initial impressions.

''If I had to pick one thing that's different, I'd say his voice in the locker room,'' Hasselbeck said. ''He's a lot more confident since I've been here. He's always been good, but he's really comfortable with it now.''

NOTES: Jeffery, cornerback Tracy Porter, offensive lineman Jason Weaver, running back Daniel Thomas and tight end Chris Pantale all missed practice with injuries. Linebacker Jared Allen was given an extra day off for Chicago. ... Three other Bears - linebacker Pernell McPhee (knee), defensive lineman Brandon Dunn (quad) and offensive lineman Jordan Mills (calf) - all left practice early.

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