The South Korean has been struggling in recent weeks and had surgery now to allow him to be fit for the start of Swansea 's pre-season preparation .
Ki Sung - yueng has had a minor knee operation and misses out for Swansea .
The South Korean has been struggling in recent weeks and had surgery now to allow Ki Sung - yueng to be fit for the start of Swansea 's pre-season preparation .
Ki Sung - yueng has had a minor knee operation and misses out for Swansea .