Weiss confirmed to BBC Scotland earlier this month that he planned to hold further talks with Hearts about becoming their next manager.
But he emerged as favourite to land the Slovakia job after their football federation announced that Jan Kocian's contract was to end on 30 June.
Now former France manager Santini and former German international Matthaus have emerged as possible candidates for the Hearts job.
Hearts announced in January that they were on the lookout for a new manager.
Stephen Frail took charge of the team for most of last season after Anatoly Korobochka returned to his role as director of football.
However, Frail is expected to sever his ties with the club after he was told to stay away from pre-season preparations.
The Tynecastle club had originally hoped to bring in Mark McGhee as their new manager, but he decided to remain with Motherwell.
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