Ki vows to fight for his place at Swansea
The South Korea international, who featured at the World Cup, returns to the Liberty Stadium after spending the previous campaign at fellow Premier League side Sunderland.
He started in Swansea's 4-0 friendly win at Plymouth Argyle last Sunday and played an hour of the 2-0 win over Exeter City on Tuesday.
The 25-year-old midfielder, who helped Swansea win the League Cup in 2013, recognises that there is much competition for a starting berth at the Welsh outfit but is confident he can be a valuable asset to the team.
Speaking to the club's official website, he said: "It's good to be back. After the World Cup I had three weeks off before I joined up with the team.
"Now I want to get as fit as I can so I can prove myself in the team.
"It was a very good time for me at Sunderland. I showed that I can help the team, so I hope to do that at Swansea [too].
"There is always competition for a position here - that goes for every player.
"If you play well then you will play, if not you will be on the bench or not involved, but I will push myself as hard as I can.
"Everyone in this team has great quality. Every season Swansea get stronger and stronger.
"With the mix of new players along with the players here last year, it will be a good balance."