RB Leipzig striker Timo Werner is out of Germany's World Cup qualifiers in Northern Ireland and against Azerbaijan with injury, the German Football Association (DFB) has announced.
Coach Joachim Low has opted not to call up a replacement, the DFB said.
Germany head to Belfast five points clear of second-placed Northern Ireland at the top of Group C, and need a point to be certain of their place in Russia next summer.
Werner has been undergoing tests after suffering "breathing and circulation problems" during RB Leipzig's Champions League game at Besiktas because of the high level of crowd noise.
He had to be substituted and did not play in the club's Bundesliga game against Cologne at the weekend.
Leipzig sporting director Ralf Rangnick told kicker: "It does not make sense to send him to the national team when the diagnoses are not finished.
"Of course we are concerned, and we just need to see Timo get well again."