The 28-year-old became the first Belgian footballer in Rovers' history when he signed a two-year deal, with the option of a further 12 months in the summer of 2020.
Arriving from KAA Gent for an undisclosed fee, the stopper has almost 300 career appearances and Champions League experience under his belt.
Kaminski started out at Beerschot AC in his homeland, making his professional debut in the Belgian top flight at the age of just 16.
Signed by Anderlecht in 2012, he won two Belgian league titles and three Belgian Super Cups, before having loan spells with Αnorthosis Famagusta in Cyprus and FC Copenhagen in Denmark, where he won both the Danish Superliga and Danish Cup in 2015-16.
After a successful spell back in Belgium with KV Kortrijk, the talented shot-stopper joined Gent in January 2019 and started all 29 of their top-flight fixtures last season, keeping 10 clean sheets in 2019-20, before the campaign was cut short due to COVID-19.
The Belgian Under-21 international also played all 14 Europa League games for Gent in that season, helping them reach the knockout stage.