The 31-year-old is a free agent after his contract with FC Sion ended last season.
Left-back Ziegler previously played in England with Tottenham Hotspur and Wigan Athletic.
RTS report Leeds have been in touch with Ziegler over a move, although gives no indication of how close a deal is.
Ziegler has 35 international caps for Switzerland which include appearances at the last two World Cups.
He has previously played for Juventus, Fenerbahce, Hamburg and Lokomotiv Moscow.
Leeds have already looked to the Swiss league once this summer, buying Macedonian international Ezgjan Alioski from Lugano.
Ziegler could compete with his compatriot Gaetano Berardi for the Leeds left-back spot if he signed, but he also can play at centre-back, another position of need for the Whites.