In scary news for NBA fans, Warriors head coach Steve Kerr will miss the remainder of Golden State’s first-round series against Portland—and potentially longer—with a mysterious illness. Kerr sat out Game 3 last night, and after the game Marcus Thompson, the San Jose Mercury News Warriors beat writer, had more detail on his situation.

Per Thompson, Kerr has been in excruciating pain throughout this series and at times “he could barely walk.” Kerr has not had this feeling before, and the Warriors have simply labeled it “illness” because they don’t really know what’s going on. We can only hope it’s a fleeting thing that’s not too serious.

Kerr missed the first 43 games of last season, but that was because of back problems—he was recovering from a notably arduous surgery. The Warriors were tremendous with Luke Walton at the helm, going 39-4 en route to reeling off the best regular season record in NBA history. This is the playoffs, though, and Kerr is one of the best coaches in the league, so the Warriors miss him badly. 

Stephen Curry took the game ball with him Saturday night after the Warriors escaped in Portland, 119-113. He planned to give it to Kerr.

“We’ve got his back,” Curry said.

A source told Thompson that Kerr will definitely not return this series.

“Oh no,” the source said. “He thinks like a player does, wanting to get back. But he’s got to get right.”

Lead assistant Mike Brown, who got plenty of NBA head-coaching experience with the Cavs and Lakers, will fill in until Kerr can return. The Warriors are up 3-0 on the Blazers and will try to finish the series off Monday at 10:30 p.m.