Spurs are sweating on the fitness of Son Heung-min, with manager Nuno Espirito Santo admitting the forward is ‘not so well’ after suffering a calf problem.

The South Korea international looks likely to miss Saturday’s trip to Crystal Palace having picked up the knock on international duty.

Nuno is unsure how long he could be without Son, with doctors set to determine whether the injury will keep him out for the long term.

‘Like some of our players, he came (back) with some issues.

‘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,’ the Spurs boss said.

‘I don’t know (if it’s long term). Let’s wait and see. The doctors will make the proper diagnostics.’

Son is one of a number of injury concerns after the international break, with Steven Bergwijn, Oliver Skipp and Ryan Sessegnon also set to be checked over by club doctors before it’s decided whether they can feature at Selhurst Park.

‘Let’s wait and see. We have to assess, speak with a medical department and make the decision on the squad for tomorrow,’ Nuno said.

They will definitely be without South American trio Giovani Lo Celso, Davinson Sanchez and Cristian Romero, who are all in quarantine in Croatia after defying Spurs and heading to red-list countries.

Spurs head to Palace looking to maintain their perfect start to the Premier League season. They have won all three matches under their new manager 1-0, a run which earned Nuno the manager of the month award for August.

‘The award is for everybody. It’s for the football club, especially for the players as they are the ones since day one committed themselves. And they won the three games,’ he added.