However the Cavaliers traded him and Cliff Robinson to the Washington Bullets for Melvin Turpin on the day he was drafted.

He had a strong start to his NBA career, averaging 9.3 points per game in his rookie season.

McCormick was traded to the Philadelphia 76ers with Danny Vranes for Clemon Johnson and a 1989 1st round draft pick (Shawn Kemp was later selected) on September 29, 1986.

On January 16, 1988, McCormick was traded by the Philadelphia 76ers with Roy Hinson and a 1989 2nd round draft pick (Stanley Brundy was later selected) to the New Jersey Nets for Ben Coleman and Mike Gminski.

McCormick averaged a career high 14.1 points per game during the remainder of the season in his time with the Nets.

While McCormick statistically played a lot better in New Jersey, the Nets were a rebuilding team and posted a horrendous 19–63 record.

On November 2, 1988, McCormick was traded by the New Jersey Nets with Tony Brown, Frank Johnson and Lorenzo Romar to the Houston Rockets for Joe Barry Carroll and Lester Conner.

On September 27, 1990, McCormick was traded by the Houston Rockets with John Lucas and a 1994 1st round draft pick (Charlie Ward was later selected) to the Atlanta Hawks for Roy Marble and Kenny Smith.

On October 3, 1991, McCormick was traded by the Atlanta Hawks with a 1994 1st round draft pick (Charlie Ward was later selected) to the New York Knicks for Maurice Cheeks.

In the second round the Knicks faced a very difficult opponent, the Chicago Bulls who were led by the dominant Michael Jordan and were in the middle of their first 3-peat.