Michael Porter Jr. is among the most skilled and talented players in the draft, but questions remain about his durability and injury history. (0:44)

An invitation-only medical examination of Missouri freshman star Michael Porter Jr.'s surgically repaired back will go forward on Friday in Chicago, his agent, Mark Bartelstein, told teams in an email Thursday afternoon.

Porter was scheduled to hold a workout for teams Friday in the city, but canceled it because of a strained hip. It brought into question whether he would even be made available for the medical exam.

Porter's agency, Priority Sports, had previously informed teams that they could bring their own trainer and doctor for a 15- to 20-minute evaluation, a unique twist in the draft environment.

Porter is No. 7 in ESPN's most recent mock draft. He also was suffering from back spasms Thursday and underwent an MRI, and it was expected that he'd be evaluated again Thursday night, although he was said to be feeling better.

Porter's camp appears to feel comfortable with his stock. The Sacramento Kings (No. 2), Memphis Grizzlies (No. 4) and Dallas Mavericks (No. 5) are interested in Porter, and it's now unlikely he falls out of the top seven in the draft, sources tell ESPN.com. The Chicago Bulls hold the seventh pick.

Porter's draft stock appeared to be trending down after the college basketball season, as his refusal to participate in the NBA combine medical examinations and the postponement of his first pro day -- originally scheduled for June 1 and rescheduled to June 8 -- caused some teams picking in the late lottery to believe Porter might still be on the board for their pick. Questions about his ability to be a good teammate at Missouri and his pre-draft interviews with NBA teams attending the combine contributed to the concern.

Porter dropping to the late lottery would be a noteworthy turn of events for a player rated so highly in his high school class. For much of 2017, Porter was projected to be one of the top two picks in the 2018 NBA draft.

A back injury revealed in late November derailed Porter's freshman season, forcing him to have microdiscectomy surgery on his L3 and L4 spinal disks. Porter was cleared to play in March and participated in two games for Missouri, shooting 9-for-29 from the field.

Porter ceased all basketball activity after the season, focusing his efforts on rehab, sources told ESPN, after losing strength in his left leg in particular because of the injury. He was cleared to play just two weeks before his June 8 pro day. While he reportedly felt only about 50 percent physically, he had an impressive showing, according to multiple teams in attendance, as he shot the ball exceptionally well. His size, fluidity and shot-making ability off the dribble reminded teams of the player who had been highly touted before the season.

The results of Porter's full medical examination, conducted by the Bulls, were eventually released to all NBA teams. Representatives of multiple teams that reviewed the information with their medical staffs say those results are encouraging.

"There doesn't appear to be anything wrong with him right now," one NBA executive told ESPN.com. "But a conservative doctor could still [be concerned about] what might happen down the road."

League sources say that NBA doctors appear optimistic about his long-term prognosis, and teams will weigh his talent against the inherent risks.

"Everyone is worried about missing out on a star," one NBA executive told ESPN. "No one wants to miss out on another Joel Embiid."