Two years into his professional career, McGinnis was selected by the Philadelphia 76ers as the 22nd overall pick in the second round of the 1973 NBA draft. In October 1974, the 76ers were ready to send McGinnis' draft rights to the New York Knicks with the stipulation that the latter ballclub signs him before the agreed-upon deadline. The deal fell through when he decided to stay with the Pacers and signed a two-year contract with an $85,000 buyout clause which was exercised following the 1974–75 season. Preferring to play in New York because of its financial endorsement opportunities, McGinnis sought a preliminary injunction and restraining order against the NBA on May 23, 1975 that would have permitted him to negotiate with any of the league's 18 teams. The lawsuit was dropped a week later on May 30 when he signed a six‐year $2.4 million contract with the Knicks in a challenge to the league's constitution. In his first action as new NBA commissioner on June 5, Larry O'Brien disapproved the contract and ordered the Knicks to forfeit its first selection in the 1976 NBA draft and reimburse the 76ers for all expenses relevant to the dispute. McGinnis signed a six‐year, $3.2 million guaranteed, no‐cut, no‐trade, no-option contract with the 76ers five weeks later on July 10, 1975.