Earlier on Sunday, he signed a 10-day contract with the Brooklyn Nets.
Collins entered the court at the start of the second quarter in a game against the Los Angeles Lakers.
The 35-year-old centre, who has played for five other NBA teams, was given a warm reception by the crowd.
He only revealed he was gay in a Sports Illustrated magazine interview last April.
At the time he was not signed to a team.
Needing another big man, the Nets turned to the seven-foot Collins, who helped them reach two NBA Finals in the early 2000s.
“The decision to sign Jason was a basketball decision,” general manager Billy King said in a statement.
“We needed to increase our depth inside, and with his experience and size, we felt he was the right choice for a 10-day contract.”
The news comes as Michael Sam, another US sportsman who recently revealed he is gay, prepares to take part in American Football’s NFL Scouting Combine – a showcase of college players looking to be signed by NFL teams.
Last May, Los Angeles Galaxy footballer Robbie Rogers became the first openly gay male athlete to play in a US professional league.
However Major League Soccer is not regarded as one of the four main sports competitions in the US.
