In the 2007–08 season, due to an injury to Jacek Banaszyński, Sandomierski made his Ekstraklasa debut against Cracovia in which he conceded two goals.

[3] In August 2011, Sandomierski signed a five-year contract with Belgian champions Genk, as a replacement for Thibaut Courtois.

[5] He made his debut for Rovers against Cardiff City in a 3–0 defeat conceding two goals one of which was a penalty, coming on for injured counterpart Jake Kean in the 52nd minute.

Caretaker manager Gary Bowyer expressed his faith in the Polish international, however Rovers were beaten 3–2 on the day.

[11] On 13 January 2023, at the age of 33, he ended his professional football career and joined Jagiellonia Białystok youth team and KS Turośnianka as a goalkeepers' coach.