AUSTIN, Texas — Dennis Johnson, the star NBA guard who was part of three championships, died Thursday, collapsing after his developmental team’s practice. He was 52.

Johnson, coach of the Austin Toros, was unconscious and in cardiac arrest when paramedics arrived at Austin Convention Center, said Warren Hassinger, spokesman for Austin-Travis County Emergency Medical Services.

Paramedics tried to resuscitate him for 23 minutes before he was taken to a hospital and pronounced dead, Hassinger added. Mayra Freeman, a spokeswoman for the medical examiner’s office, said there will be an autopsy.

The Toros postponed home games Friday and Saturday nights, the NBA Development League said.

“Dennis was a great player, one of the best teammates I ever had, and a wonderful person,” said former teammate Larry Bird, now president of the Indiana Pacers. “My thoughts and condolences are with his family at this difficult time.”

Johnson, a five-time All-Star and one of the top defensive guards, was part of the last Boston dynasty. He spent 14 seasons in the league and retired after the 1989-90 season. He played on title teams with the Celtics in 1984 and 1986 and with the Seattle SuperSonics in 1979, when he was the NBA Finals MVP.

He is survived by his wife, Donna, sons Dwayne and Daniel, and a daughter, Denise.