|Petrovic effectively replaces the departing Jelena Dubljevic|
The forward will make the Czech capital her new home after spending six years playing in the competition for Vidnoje, with the former four-time winners absent from the 2014-15 tournament.
Last year Petrovic was one of the standout performers in EuroLeague Women and averaged 14.4 points, 7.4 rebounds and 2.6 rebounds per game.
Having previously played a season with Tango Bourges prior to her lengthy spell in Russia, Petrovic moves to the Czech champions as a replacement for Montenegrin star, Jelena Dubljevic who has not been offered an extension.
"We have taken a while to decide whether to extend the contract with Jelena," confirmed USK Prague General Manager, Marek Kucera.
"She had an amazing season, but at the Final Eight of EuroLeague Women she had health problems and that was the main reason why we finally decided not to continue our co-operation.
"At the most important stage of the season, Jelena was not available and we did not want to risk that happening again.
"Sonja is a player that plays a little different style than Dubljevic, among the advantages include the fact that she plays for the team.
"Moreover, she wanted a change of scenery and we are pleased that we have agreed to her co-operation."
He added, "We have signed her on a contract for two years."
It means the USK Prague roster is all but complete and at this stage, the forward line looks to be stacked.