Erin Popovich, the wife of San Antonio Spurs head coach Gregg, died on Wednesday, the NBA team announced.

Details of Erin's death were not disclosed by the Spurs, though she was reportedly ill over an extended period of time.

The 69-year-old Gregg Popovich – a five-time NBA championship-winning coach – and Erin were married for 40 years.

In statement, Spurs general manager RC Buford said: "With deep regret the San Antonio Spurs announce that Erin Popovich, wife of Spurs coach Gregg Popovich, passed away earlier today.

"Erin and Gregg were married for four decades and were blessed with two children and two grandchildren. We mourn the loss of Erin. She was a strong, wonderful, kind, intelligent woman who provided love, support and humour to all of us."

The Spurs host reigning NBA champions the Golden Warriors in game three of the Western Conference quarterfinals on Thursday. 

Warriors star Kevin Durant was saddened to hear of Erin's passing on Wednesday. 

"What? Seriously? Man, prayers and condolences to his family. Damn. I don't even know what to say," Durant said when he learned of the news.

"The whole NBA family is supporting him, got his back through it all. Feel so bad for Pop."