The South Korean winger has already been ruled out by injury earlier this season, missing their clashes with Manchester United, Ferencvaros and Brighton in early October. He did, however, return to the starting line-up against West Ham, scoring Tottenham's fourth and final goal before he was then taken off in the 70th minute looking uncomfortable.
Having missed the game against Alkmaar, Son also sat out training, and Postecoglou confirmed he didn't take part in the session on Friday either. If he does miss the Palace game, it will allow Son to rest up and be fully fit for games against Manchester City and Aston Villa in November.