Injury to the Gracilis muscle is common among track dogs but is not as common in hunting dogs I think its usually a tear in the muscle or it can become completely detached from the bone, if its torn then plenty of rest and sessions in the mag box might help if its detached its an expensive operation with good chance the dog will be hampered by it in future second vet opinion might be worthwhile one clued up on coursing dogs one is Paul Evans in Royton Lancashire clued up and doesnt bull shit