[Huw Evans Agency]Harry Darling missed Swansea City's defeat at Millwall on Saturday after suffering a knee injury in what Alan Sheehan described as an "accident" on the morning of the game.Defender Darling, 25, had been due to start at The Den, but had to be replaced in Swansea's XI by Hannes Delcroix."He had an accident this morning," caretaker boss Sheehan said."I don't want to go too much into that. It's unfortunate, but we need to look at that."Darling is out of contract this summer, though