Left Full-Back Lappin, 30 joined the Bluebirds from Norwich City in July 2013 on a free transfer after playing 107 times in five years for the Canaries but he has yet to feature in the Welsh sides first season in the Premier League.
Any move is likely to only involve a loan move with the transfer market firmly shut until 1 January 2014 - he could make his debut at home to Crawley Town tomorrow should he make the switch to S2.