The midfielder has "extra bone growth" in the joint to rectify, leaving the player "bitterly disappointed".

He added: "I started to feel some pain in my ankle after returning from the training camp in America.

"I saw a specialist last week and the MRI scan revealed the extra bone growth at the back of my ankle. There is not a lot I can do about it."

Dyer says he is "determined to work even harder after my operation" to make his mark.

The 28-year-old, who won a Premier League winner's medal during a season's loan at Leicester City, signed a four-year contract extension with the club in August 2016.