Untersee joined Empoli in the off-season from champions Juventus after successfully helping the side gain promotion to the Italian top-flight during his six-month loan spell.
However, the 25-year-old, who joined the club for R7.8m, has been restricted to just three appearances in the league this season.
Swiss giants FC Zurich have subsequently snapped him up on a temporary switch for the rest of the season, rejoining the club he left eight years ago as an U-18 academy product for Juve.
Untersee becomes the second player of South African heritage at the 12-time Super League champions after winger Marvin Graf.
Zurich take on Grasshoppers in their next league fixture on February 9 before a knockout Europa League tie against Napoli five days later.