Holmgren has been ruled out for Thursday's Summer League matchup against the 76ers for an undisclosed reason, Joe Mussatto of The Oklahoman reports.
Holmgren posted a double-double during Wednesday's Summer League loss to the Grizzlies, but he'll be inactive a day later. It's unclear whether he's dealing with an injury, but his next opportunity to suit up will be Saturday against the Mavericks.