Denver, Colorado is 5,280 feet above sea level, and Tottenham Hotspur, along with most of the MLS All-Stars, won't be used to playing in those conditions.
"It's going to be a tough training session for us this afternoon and a tough game for us on Wednesday at this altitude, on top of the hotness" said Spurs midfielder Nabil Bentaleb.
"We had a gym session earlier, and it was quite tough," said forward Harry Kane. "We train this afternoon so we'll probably get a bit more used to it, being outside."
"It'll probably be the toughest that I've faced in my career, so I'm looking forward to it. It'll be a good test and it'll be great for our fitness ahead of the new season," Kane said.
"I think it's good to go out an get the training session this afternoon so we can adapt to it and hopefully know what's oming our way really when we come to the game Wednesday night," said defender Kyle Walker.
Tottenham won't be alone facing altitude-related difficulties, as the only MLS All-Star from the Colorado Rapids is defender Drew Moor.
Contact The18 Staff Writer Sam Klomhaus at Klomhaus@The18.com or follow him on Twitter @SamKlomhaus