CHICAGO — Bobby Portis dressed slowly and walked gingerly out of the postgame locker room Wednesday night, headed to an all-too-familiar place for the 2018-19 Bulls.

A doctor’s visit.

Portis underwent an MRI on his injured right knee Thursday morning that revealed a sprained MCL. It’s the same injury, but a different knee, that Kris Dunn suffered on Monday in Dallas.

Like Dunn, Portis faces a four- to six-week timeline for recovery.

The Bulls already are without Lauri Markkanen, Denzel Valentine and Dunn, who have played a combined one game between them.

Markkanen suffered an elbow injury during the first week of training camp that has sidelined him to mid-November at the earliest. Valentine sprained his surgically repaired left ankle during the first week of training camp and will be re-evaluated in one week, with no timetable for his return. And Dunn will miss four to six weeks after he went down in his season debut in Dallas, spraining his left MCL while scoring on a layup.

Portis suffered his injury during the fourth quarter of the Bulls’ first victory of the season over the Hornets. He screamed in pain and ran off the court, directly past reporters sitting on press row. Portis continued to run towards the stands, eventually crumpling up with his head down.

Portis walked off under his own power and left the locker room doing the same. He was headed to undergo tests after doctors made a preliminary diagnosis of the injury.

Portis recently turned down a contract extension offer and will be a restricted free agent next summer. Before starting for the injured Markkanen, he vowed to vie for the NBA’s Sixth Man of the Year award.

The Bulls, who were scheduled to fly to Charlotte, N.C., didn’t practice Thursday. But all signs point to Jabari Parker starting at power forward.

“If I start, we had some glimpses in that fourth quarter with me, Justin (Holiday), Zach and those guys,” Parker said. “You have to be prepared.”

Still, even if the Bulls are temporarily granted an extra roster spot via the NBA’s hardship provision, it’s a significant blow for an organization that looked to build chemistry and cohesion in the second season of its rebuild. In Markkanen, Dunn, Portis and Valentine, the Bulls are missing four players who combined to average 52 points and 23.7 rebounds last season.

“Nobody is going to feel sorry for you in this league,” coach Fred Hoiberg said recently. “This league is about opportunity.”