INDIANAPOLIS, IN - JANUARY 01: Andrew Luck #12 of the Indianapolis Colts throws a pass durling the game against the Jacksonville Jaguars at Lucas Oil Stadium on January 1, 2017 in Indianapolis, Indiana. (Photo by Andy Lyons/Getty Images)

Former No. 1 overall pick could be out until at least October

One of the league's best young quarterbacks was already expected to miss his season opener on Sunday.

Indianapolis Colts quarterback Andrew Luck was already expected to miss Sunday's season opener against the Los Angeles Rams. But according to NFL Network's Ian Rapoport, the former No. 1 overall pick could miss even more time than that.

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Rapoport reports that Luck could be out until at least October as he recovers from a shoulder injury.

"You mentioned the return of Andrew Luck, of course, it's not going to be this week," Rapoport told NFL Network. "It's going to be Scott Tolzien as their starting quarterback and my understanding is we're still a couple weeks away at least from seeing Andrew Luck. The reason is, of course, he came off the PUP list to much fanfare, back at practice, except he didn't actually practice this week and it remains to be seen whether or not he'll still be on the practice field next week. The Colts and Tolzien are preparing for an extended stint here and it sounds to me like October is a better goal for when we might see Andrew Luck on the field. Jim Irsay mentioned he needs to trust his arm, that is where it stands now for Andrew Luck."

Luck underwent shoulder surgery this offseason, but is nearing completion of  program to build strength in his throwing shoulder, sources close to the situation reported to CBS Sports.

The Colts are clearly being cautious with their franchise quarterback, although many still expect Luck to take a "sooner rather than later" approach in making his debut at practice.