Three explosions rocked the Borussia Dortmund bus, injuring Spanish international Marc Bartra, as the German team headed for a Champions League game against Monaco on Tuesday, police said.
Bartra was taken to hospital and the quarter-final match was postponed until Wednesday because of the attack.
Other Dortmund players were said to be "shocked" but safe.
The bus had set off from the team hotel for the Borussia stadium about 10 kilometres (six miles) away when "three explosive charges detonated," said police spokesperson, Gunnar Wortmann.
The explosives, which went off shortly after 7.00 pm (1700 GMT), were hidden in a hedge and were set off as the bus passed, according to German media.
Security sources said there was no immediate sign of an organised "terrorist" attack, the German news agency reported.
The bus windows were shattered and the bus was burned on the right hand side.
Dortmund chief executive Hans-Joachim Watzke said Bartra, 26, was being treated in hospital for a hand injury.
The club said other players were safe and there was no danger inside the Signal Iduna Park stadium.
TRT World's Ira Spitzer reports.