The Wanderers wing-back has a history of knee trouble, having twice required an operation in America to repair ligament damage over the last five seasons.
This new setback has prompted concerns that the 26-year old may miss a large chunk of the pre-season programme both on the domestic and international front.
Gardner is expected to see Dr Richard Steadman over the coming weeks to determine the extent of the damage which, if as bad as first feared, will keep the Reggae Boy out of action for the opening month of the season - if not more.
Colorado-based Steadman is a surgeon who has operated on the Jamaican before, so he has all the necessary know how in determining the extent of such an injury.
Hopefully the medical tests will come back all-clear to enable Gardner to play a part in Bolton's Premiership opener in just under two months from now.