Larry Johnson vs Alonzo Mourning
Larry Johnson and Alonzo Mourning were the first and second picks (respectively) in the 1991 and 1992 drafts, taken by the Charlotte Hornets. Initially, Johnson went out of his way to let Mourning know that the Hornets were his team, as Johnson won the 1991 Rookie of the Year award, and Mourning didn’t. Even though the two were supposed to the cornerstones of an up-and-coming Hornets team that won 50 games at its peak, their battles for “top dog” badly damaged what could have been a very bright future.
After Mourning rejected contract extension offer with Charlotte, and with Johnson losing a step due to a back injury he suffered, Charlotte ended up trading both players between 1995 and 1996.