Kleindienst has been rewarded after his fine Bundesliga form last season as his 12 goals for Heidenheim helped them finish in a surprise eighth place.
Kleindienst has added another two league goals along with one assist since joining Gladbach this season.
West Ham United forward Fuellkrug has been nursing a foot injury for the past few weeks and has been out of action.
"Tim Kleindienst at Heidenheim performed well over an entire year and he has integrated himself well at his new club Borussia Moenchengladbach," said Germany coach Julian Nagelsmann.
"He has earned this. The injury to Niclas Fullkrug is a good opportunity to test Tim. He now has to prove himself."
Germany travel to face Bosnia in Zenica on October 11th before hosting the Netherlands three days later.
The Germans are top of Group A3 on four points from two matches, ahead of the Dutch on goal difference. Bosnia and Hungary have one point each.
