The German midfielder only joined Spurs in January 2013 in a cut-price deal, but he’s struggled to make himself a regular at White Hart Lane.
Last term the 23-year-old was shipped out to Fulham for the end of the campaign, where he was impressed.
But new boss Mauricio Pochettino is understood to have assessed him during pre-season and has now reached the conclusion that he can be sold.
QPR and Palace are leading the race for his services, with both London clubs eager to bring in the versatile star.
The Super Hoops are perhaps the more likely side to land him, with the Eagles currently in a state of turmoil following Tony Pulis’ surprise exit.
Holtby himself is said to be happy at White Hart Lane, yet if his first-team opportunities are due to be rationed he may opt to leave.
Schalke have been linked with a move to get him back to Gelsenkirchen in the past.