Andrew Luck: Indianapolis Colts QB likely out for 'several more weeks'

Sept. 10 (UPI) -- Pro Bowl quarterback Andrew Luck has no timetable to return to the Indianapolis Colts, according to sources.

Sources with knowledge of the situation told CBS Sports that Luck has not entered the intensive throwing portion of his recovery from shoulder surgery. He is close to completing a program aimed at rebuilding the strength in the throwing shoulder, according to the report. The report also stated that a practice debut for Luck is expected "sooner rather than later."

In the meantime, the Colts turn to Scott Tolzien. The five-year veteran will start Sunday against the Los Angeles Rams.

Luck, 27, completed 63.5 percent of his passes for 4,240 yards, 31 touchdowns and 13 interceptions in 15 starts last year for the Colts. The No. 1 overall pick in the 2012 NFL Draft began his career by making three consecutive Pro Bowls, but hasn't been back since the 2014 season.

Luck had right shoulder surgery in January, but has been bothered by shoulder pain since 2015.

Tolzien is 0-2-1 as a starter during his NFL career.

"It's an honor, but at the same time you've got to approach it as the starter all the time, no matter where you are on the depth chart," Tolzien told Colts.com on Monday. "I've said that before, and that holds true: you should always be preparing like the starter, and I'm excited for the opportunity."

The Rams ranked No. 10 in pass defense last season.