Polen has run into a tough setback ahead of the EM. Forward Arkadiusz Milik will miss the tournament after being knee-injured during the EM rehearsal against Ukraine on Friday evening.
The 30-year-old Juventus forward will need to undergo an operation on his knee.
"The player will return to his club to undergo an arthroscopy," writes the Polish Football Association on its website.
Poland suffered several injuries in the 3-1 win over Ukraine in Warsaw. Nicola Zalewski, Michal Skoras, Bartosz Salamon, Jakub Kiwior, and Kacper Urbanski all took knocks, but none serious enough for them to leave the team at present.
Poland will play its first match in the EM against the Netherlands on June 16 and also has Austria and France in its group.