The 26-year-old broke a toe in his right foot in Bayern Munich's 1-1 draw with Eintracht Frankfurt on April 23 in the German league, but the club kept the injury a secret to ensure he could finish the season.
Schweinsteiger sat out Bayern's 4-2 win at Russia's Zenit St Petersburg on Wednesday in their final friendly before breaking up for summer and Germany's vice-captain is battling to be fit to add to his 87 caps for his country.
"We had deliberately not disclosed the injury," Bayern's media director Markus Hoerwick told Munich newspaper TZ. "The risk that someone would tread on Bastian's foot was too big."
Although Schweinsteiger managed to play three league games with the broken toe, the injury has got worse.
Germany have back-to-back Euro 2012 qualifiers against Austria, on June 3 in Vienna, and Azerbaijan, on June 7 in Baku.
"I do not know yet (if I can play)," he told German daily Bild.