He was traded on draft day to the Houston Rockets in exchange for their pick, Joel Przybilla.

With the Hawks, Collier dropped a career-high 22 points on March 12, 2004, in a 138–124 win against the Washington Wizards.

Although he was Atlanta's starting center for that game, he only played for nine minutes and had two points and one rebound on 1-4 field goal shooting.

During the NBA off-season, Collier died suddenly at the age of 28 on October 15, 2005, in Cumming, Georgia.

The Hawks wore permanent black shoulder patches on their uniforms to honor Collier.