
The 30-year-old Glik, a stalwart of the Polish defense, injured a shoulder a little after the FIFA deadline for naming the final squad.
“During a training session, Kamil Glik suffered a ligament injury to his acromioclavicular joint,” the Polish football federation said in a statement.
The Monaco defender underwent preliminary tests in Poland but will on Tuesday fly to Nice for further treatment before a decision is taken on his rehabilitation with a view to a return to full training, it added.
“He remains on our list. We await the results of the test,” federation spokesman Jakub Kwiatkowski said.
If Glik’s injury were to prove serious, he would be replaced by Stuttgart’s Marcin Kamiński, according to Nawałka.
Before heading to Russia on June 13, Poland have warm-ups against Chile in Poznań on June 8 and Lithuania in Warsaw four days later.
In Russia, Poland open their Group H campaign against Senegal in Moscow on June 19 before facing Colombia and Japan.