Napier is the third Heat player to see his season end early, along with center Chris Bosh and forward Josh McRoberts. Bosh will not play until next season because of blood clots on a lung, and McRoberts is still rehabilitating after knee surgery.
Napier played in 51 games this season for the Heat, making 10 starts. The former Connecticut star who led his team to last year's NCAA championship averaged 5.1 points, 2.5 assists and 2.2 rebounds in his rookie year.
The Heat start a three-game road trip in Cleveland on Thursday, then visit Detroit and Indiana this weekend.