Austin, Texas ? Dennis Johnson, the star NBA guard who was part of three championships and teamed with Larry Bird on one of the great postseason plays, 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 tonight and Saturday night, the NBA Development League said.

“He was one of the most underrated players in the history of the game, in my opinion, and one of the greatest Celtic acquisitions of all time,” said former Boston teammate Danny Ainge, now the Celtics’ executive director of basketball operations.

“D.J. was a free spirit and a fun personality who loved to laugh and play the game. We had spoken at length just the other night about basketball and his excitement about coaching the Austin Toros. “

Johnson played Toros player Jamar Smith in a game of 1-on-1 after practice and everything seemed normal, player Anthony Fuqua said.

“He was being Coach Johnson out there, talking trash, playing basketball, dribbling around and shooting,” Fuqua said. “Everything seemed fine. We’re all in shock.”

Toros spokeswoman Perri Travillion said she was talking with Johnson on the sidewalk outside the building when he collapsed. Johnson was joking about getting a parking ticket.

“We were laughing,” she said. “He just collapsed.”

Travillion said she called 911 and that Johnson never regained consciousness. She said Johnson did not appear to have overexerted himself at practice and didn’t complain of any discomfort before he collapsed.

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.

Johnson was a favorite teammate of Bird’s, and the two were part of one of the most memorable plays in Celtics history.

During the fifth game of the 1987 Eastern Conference finals against Detroit, Bird stole Isiah Thomas’ inbounds pass under Boston’s basket and fed Johnson, who drove in for the winning layup.

Boston won the series in seven games, but lost to the Los Angeles Lakers in the NBA Finals.