Career
An outspoken wingback and freekick specialist, Polak previously played for Excelsior Rotterdam,, and ADO Den Haag. In May 2008, Sparta announced that they would not extend his contract. After that, Sjaak had several trials, in Austria for example with Austria Vienna and with Swiss club Saint Gallen, but without success.
He ended up in Israel, where he is currently trialing with Maccabi Tel Aviv.