A large number of the Ukraine players have been suffering with food poisoning just days before the nation co-hosts Euro 2012.
Up to 10 players are believed to have contracted the illness during a recent training camp.
Discussing the health of his squad, coach Oleg Blokhin refused to rule out foul play.
"It happened in Germany, but it is impossible to establish the causes - all ate different food," Blokhin told Ukraine television.
"It may have been sabotage, I do not know. It cannot be accidental."
Ukraine open up their campaign on Monday evening against Sweden.
