"(Undav) has a bit of an adductor problem, it's nothing structural," Nagelsmann told ZDF before the match. "I also have a bit of responsibility to protect the lads for their clubs."
Undav had scored both Germany's goals in a 2-1 win over Bosnia on Friday. His VfB Stuttgart teammate Jamie Leweling scored on his international debut to secure the win on Monday.
Germany have already booked a place in the Nations League quarter-finals and will conclude their group stage campaign by playing Bosnia and Hungary next month.