Tottenham captain Son Heung-min likely to miss away trip to Crystal Palace
Son, who missed South Korea's World Cup qualifiers this month following a hamstring injury, felt sore after scoring in last weekend's win over West Ham United and was left out of Thursday's Europa League clash with AZ Alkmaar.
"Sonny is still not right. He's still not feeling 100%, so he won't train today," Postecoglou told a press conference ahead of Sunday's match.
"He's unlikely for the weekend and we'll see how he is beyond that."
Postecoglou, however, was happy with how midfielder James Maddison stepped up to lead the team as Spurs notched up a 1-0 win over the Dutch side.
"He's a vice-captain, one of our leaders," the manager said.
Spurs, seventh in the league with 13 points from eight matches, have struggled to build a winning streak. But the 59-year-old, who joined last year, said the team was more consistent than last season, when they finished fifth.
"Results last year were great and playing on a lot on enthusiasm and energy we had. But I knew that wasn't sustainable and pretty quickly we found that out," he added.
However, the manager cautioned against underestimating 18th-placed Palace, who are winless in the campaign with only three points.
"They're going through a tough spell, but they've still got talent in that team," he said.
"You get a feeling with them that, once they do turn it around, they could go on a run like they did last year."