The Tarrant County medical examiner did not list a cause of death for Tarpley, who died at a hospital in Arlington, Texas.
"The Dallas Mavericks organization is deeply saddened upon hearing the death of former Sixth Man of the Year Roy Tarpley," the team said in a statement. "Our deepest condolences go out to his family. Mavs fans everywhere will remember him fondly."
Mavs owner Mark Cuban tweeted out his condolences.
Our condolences go out to the family of Roy Tarpley. RIP Roy. Mavs fans everywhere will remember you fondly
— Mark Cuban (@mcuban) January 10, 2015
The 6-foot-11 Tarpley, the seventh overall pick in the 1986 NBA draft out of Michigan, earned the league's Sixth Man of the Year award in his second season. That was the final full season of Tarpley's career due to suspensions.
He played for the Mavericks until October 1991, when he was kicked out of the NBA for using cocaine.
Norm Sonju was the Mavericks' chief executive when he drafted Tarpley. He remembers Tarpley as "likable. He was witty. He was funny."
"It's sad. What breaks your heart is he was just 50 years old," Sonju told The Associated Press. "He potentially could have been just an incredible player."
Sonju remembered that cocaine was a pervasive threat in all big-time athletics in the 1980s, so the Mavericks did all they could in researching Tarpley's background at Michigan.
"We had people tell us to our face that he had no problems when he was at Michigan," he said.
Temptation by cocaine and alcohol, however, was already near, he said.
Tarpley played in Greece until the NBA reinstated him in 1994. He signed a six-year, $20 million contract with the Mavericks but was permanently banned from the NBA in December 1995 for using alcohol and violating the terms of a court-imposed personal aftercare program.
Tarpley, who possessed a tremendous blend of athleticism and power, averaged 12.6 points and 10.0 rebounds in 280 career games. He was phenomenal during the 1987-88 Mavs' run to the Western Conference finals, where they lost in seven games to the Los Angeles Lakers, averaging 17.9 points and 12.9 rebounds.
However, Tarpley's off-court issues were a driving force in the darkest era of the franchise's history, a span that included 10 consecutive losing seasons and 12 years without a playoff victory. Tarpley was suspended three times over the next three years.
His third suspension lasted until the 1994-95 season, when Tarpley played 55 games before receiving the lifetime ban.
After his NBA career ended, he returned to Greece, and also played in Cyprus, Russia and China. He also spent time with Wichita Falls, Sioux Falls and Michigan in the Continental Basketball Association, and Miami and Dodge City in the U.S. Basketball League, playing into his 40s.
Tarpley filed a lawsuit against the NBA and the Mavericks in 2007, in which he claimed the league and the team violated the Americans with Disabilities Act by refusing to reinstate him.
The parties reached an undisclosed settlement in 2009.
The Associated Press contributed to this report.