Nuno Espirito Santo revealed Son Heung-min is a doubt for Saturday's clash with Crystal Palace after returning injured from international duty.

The 29-year-old returned early from South Korea, missing their World Cup qualifier with Lebanon due to a calf problem suffered against Iraq.

And Nuno confirmed that Son, who has scored the most winning goals in the Premier League since the start of last term (8), may not feature at Selhurst Park.

"Like some of our players, he came back with some issues," said Nuno, who was named the Premier League's Manager of the Month for August on Friday.

"Sonny is not so well, but let's wait for the club to make the proper announcement and explain to you better what kind of injury he has."

Asked for further clarification, Nuno responded: "I don't know. Let's wait and see. The doctors will make the proper diagnostics."

The potential loss of Son will place further impetus on Harry Kane, who has been involved in 12 goals in 14 Premier League games against Palace (7 goals, 5 assists).

Indeed, only Thierry Henry (43) has scored more goals in London derbies than Kane (38) but Spurs will also be without Cristian Romero, Giovani Lo Celso and Davinson Sanchez as they look to maintain their perfect top-flight start.

When questioned on the whereabouts of his South American trio, Nuno explained: "I can tell you that they are in Croatia. That's what we decided to do to try to avoid more problems. 

"So the solution was to try to get them in a country where after that they can join the group. Now they are working with the sports science, a physio, in Croatia."