STOCKTON, Calif. — Nate Diaz was stoned in an ice bath.

The antihero of the Ultimate Fighting Championship was on his patio, neck-deep in training for his first fight in three years. He closed his eyes behind his sunglasses.

Summer in California’s Central Valley was in full heat-blast mode. Landscapers trimmed the vast lawn with their buzzing mowers while Diaz’s father-in-law tinkered with a construction project by the pool. Diaz’s friends were in the shade, smoking marijuana.

The day’s group training would begin in a while — a seven-mile run in the 100-degree heat, a middle-of-the-night session at the gym — but the biggest concern of the afternoon was running out of weed.

“So maybe now I’m hella high, but if I hop in the ice bath it’ll kick me up, wake up my cells,” Diaz said. “It turns me from ‘I don’t want to go’ to ‘let’s go’ real quic k.”