Adrian Wojnarowski joins Get Up! to break down Markelle Fultz's shoulder diagnosis and what this means for him going forward. (1:06)

Woj: Fultz and his camp believe therapy will fix his shot (1:06)

Philadelphia 76ers guard Markelle Fultz is expected to miss three to six weeks to undergo rehabilitation on his right shoulder, league sources told ESPN on Tuesday.

Fultz, the No. 1 overall pick in the 2017 NBA draft, has been diagnosed with thoracic outlet syndrome, his attorney/agent Raymond Brothers and the 76ers said Tuesday.

The condition will be treated with physical therapy. Brothers said Fultz will do his rehab in Los Angeles.

On the advice of Brothers, Fultz visited with approximately 10 specialists over the past week or so, consultations that resulted in their bringing this diagnosis back to the organization. Brothers told ESPN that thoracic outlet syndrome "affects nerves between the neck and shoulder resulting in abnormal functional movement and range of motion, thus severely limiting Markelle's ability to shoot a basketball."

There was a Sixers medical team member on each of the visits to the specialists, Brothers said.

Fultz, 20, has seen many specialists in the past year, beyond his care with the 76ers' training staff.

Brothers informed the Sixers on Nov. 21 that Fultz would seek further opinions on his shoulder before a return to the court -- a decision that the organization has left to Fultz and his management team.

Fultz has lost the ability to carry out and follow through on long jump shots, and there's been internal and external debate about how much of this perplexing circumstance is physical vs. mental.

"People were saying it was a mental problem and it is not," Brothers told ESPN on Tuesday night. "There's no way you're the No. 1 pick in the world and all of a sudden you aren't able to consistently raise your arms to shoot a basketball. Something is physically wrong. Now we have the answer to that problem."

Before Fultz stepped away on Nov. 21, it appeared backup guard T.J. McConnell would be taking over a majority of Fultz's minutes.