Swansea winger Nathan Dyer is set to undergo ankle surgery on Monday and miss the next two months.
"I am bitterly disappointed," Dyer told the official Swansea website.
"I was feeling good after completing pre-season training and being involved in the friendlies and the first three games of the campaign.
"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, but I am determined to work even harder after my operation to play my part for the team on my return."