Siakam's rehabilitation and recovery time is expected to be approximately five months.
The 27-year-old suffered the injury in a May 8 matchup against the Memphis Grizzlies. Siakam left the game with what the team called a left shoulder strain and did not suit up in any of the Raptors' final four games down the stretch.
The 2018-19 Most Improved Player and 2019-20 All-NBA team member averaged 21.4 points, 7.2 rebounds and 4.5 assists on 45.5 per cent shooting from field, struggling from beyond the arc where he connected at a 29.7 per cent clip.
The Raptors missed the playoffs this season for the first time since 2013 amid a trying campaign where they were forced to relocate to Tampa, Fla., and dealt with a COVID-19 outbreak that sent them nosediving down the standings.