Ki forced off in Swansea opener

With Swansea 2-1 down at Stamford Bridge, Ki went down holding the back of his right thigh and after receiving treatment he was forced to make way, with Jack Cork taking his place.

Ki, 26, was voted Swansea's Player of the Year by the club's supporters last season after scoring eight goals in 34 appearances across all competitions.

He joined the club from Scottish giants Celtic in a deal reportedly worth £6 million ($9.3 million, 8.5 million euros) in 2012 and returned to the Liberty Stadium last season after spending the 2013-14 campaign at Sunderland.

He has made 74 appearances for South Korea, scoring five goals.