The 31-year-old Arsenal midfielder, who has scored 20 times in 85 games for the Czechs since making his debut in 2000, said that he would be seeing a doctor prior to rejoining the squad at their training camp in Austria.
"The muscle is not torn but it is necessary for me to consult a doctor," said Rosicky, who first shone in the Czech side that reached the EURO 2004 semi-finals. "After that all being well I will rejoin the squad."
Coach Michal Bilek has taken the precaution of calling up Viktoria Plzen's young midfielder Vladimir Darida. "For the moment there is no great panic as regards the fitness of Rosicky," said Bilek. "But if towards the end of the week Tomas is still not 100 per cent ready then Darida will be selected for the EURO, at the expense of an already selected player."
The Czechs are in Group A and start off their campaign against Russia on 8 June followed by a clash with EURO 2004 champions Greece, who eliminated them in the 2004 semi-finals, on 12 June and round off their group fixtures against co-hosts Poland on 16 June.
Before leaving for Poland they have two warm-up games, against Israel on 26 May in Hartberg, Austria, and against Hungary on 1 June in Prague.