Procedure in December stalls Wiseman’s return

MILWAUKEE — Warriors center James Wiseman underwent an arthroscopic procedure in mid-December to clean up some debris around his surgically repaired right knee, a league source confirmed with The Chronicle on Thursday.

This helps explain why, nearly nine months after he underwent surgery to repair a torn right meniscus, Wiseman has yet to even be cleared for 3-on-3 scrimmages. As recently as late November, he appeared poised to return before teammate Klay Thompson, who came back Sunday from Achilles surgery.

But even though he had no structural damage in his repaired meniscus, Wiseman started to experience persistent swelling. An arthroscopic procedure got rid of loose fragments and stopped the swelling. Now, about a month removed from that minor surgery, Wiseman is finally about to get cleared for 3-on-3 scrimmages.

He recently started traveling with the team. After participating in 3-on-3 work with no issues, Wiseman will progress to 4-on-4, then 5-on-5. The expectation is that he wouldn’t need nearly as much contact work as Thompson, who scrimmaged for more than a month before returning Sunday against the Cavaliers.

The Warriors have yet to put a timetable on Wiseman’s return, but odds are he won’t come back for at least several more weeks. That could put his season debut sometime around the All-Star break in late February.

Whenever Wiseman does return, he will likely have a limited role. Center Kevon Looney has done enough to

remain the starter, but Wiseman could provide the Warriors some much-appreciated size in short bursts.

Golden State currently doesn’t have a player available taller than 6-foot-9. Come playoff time, it will need to match up with some of the league’s top 7-footers. A late-February return would give Wiseman about six weeks to get into a rhythm before the postseason.

Atkinson update: Just a couple of days after joining the Warriors for his first trip since late October, assistant coach Kenny Atkinson entered the league’s health and safety protocols Thursday.

“The guy can’t catch a break right now,” head coach Steve Kerr said. “And we need him, too, so it’s a big loss. I just feel terrible for him, and it’s very frustrating for us as a staff because he’s a huge part of what we do.”

Assistant coach Chris DeMarco replaced Atkinson, who suffered a leg injury in late October that kept him away from the team for a couple of months, on the front of the bench Thursday in Milwaukee.