Indianapolis Colts quarterback Andrew Luck's treatment and rehab of his surgically repaired right shoulder is apparently going well, but when he resumes throwing in the near future will determine whether he needs corrective surgery in January to address the setbacks that unexpectedly sidelined him for the 2017 season, sources told ESPN.

Luck is optimistic he can avoid another surgery based on the results of his extended European treatment and rehab, sources said. He is scheduled to return from his trip in the next week.

The next stage is for Luck to engage in a throwing regimen that previously resulted in a setback, with pain and discomfort in the same throwing arm that underwent surgery in mid-January to repair a torn labrum. The specific pain Luck previously experienced was attributed to biceps tendinitis, sources said.

If the pain returns during the throwing stage, an urgent discussion will occur for Luck to undergo a corrective surgery that involves relocating the biceps tendon that is attached to the repaired labrum, sources said.

In the procedure known as a tenodesis, the biceps tendon is reattached by a screw to the humerus, the long bone of the upper arm that connects the shoulder and the elbow.