Mario Gotze will not play in Borussia Dortmund's DFB-Pokal game against Eintracht Trier on Monday, coach Thomas Tuchel has said.
Gotze, who did not play in Dortmund's 2-0 Supercup defeat to his old club Bayern Munich last weekend, took part in a friendly on Monday but suffered a muscle problem in training.
Tuchel told a news conference: "Mario Gotze has complained about a slight adductor problem after training on Sunday morning, which is best described as muscle tightness.
"As a precaution, he will not play at Trier. Christian Pulisic will take his place in the squad."
Tuchel also explained that he was delaying the return of fellow midfielder Marco Reus, who was expected to return in mid-August after an adductor injury.
"The first reintegration point we had envisaged passed a few days ago. Caution enjoys the highest priority," he said.
"Since we have not counted the days and obsessively pushed for deadlines, I am only able to say he returns when he does."