Police are investigating three "serious explosive devices" which went off near the Borussia Dortmund team bus ahead of a Champions League match in Germany.
Defender Marc Bartra, a Spain international, was taken to hospital after being injured by shattered glass from the coach's windows.
He suffered a wounded hand and arm.
Other players in the German side are thought to have been unhurt.
Club chief executive Hans-Joachim Watzke said: "The team are obviously completely shocked."
The blasts happened as the vehicle was leaving the team hotel in Dortmund before a Champions League match against Monaco.
Police said the devices may have been hidden in a hedge near a parking area.
Mr Watzke said he understood the blasts were by the exit of the hotel and happened as the bus was passing.
The team's Swiss goalkeeper Roman Buerki was sitting in the back row of the bus, next to Bartra.
Buerki said players ducked for cover, wondering if there would be more explosions.
They happened 10km (6.2 miles) from the Westfalenstadion, where the team had been due to face the French side in a quarter-final first-leg tie.
The game has now been postponed until Wednesday evening.
Borussia Dortmund said there was no danger at the stadium, where around 80,000 people would have been expected for the game.
The club thanked Monaco supporters for their "patience and understanding" and for chanting "Dortmund! Dortmund!" when the reason for the postponement was announced.
Dortmund recommended that fans stay in the stadium and remain calm to allow an "orderly departure".
Mr Watzke said: "It was all very disciplined.
"I think with all the social media we have these days that people pretty much knew what was going on, and then when the postponement was announced officially."
North Rhine-Westphalia police spokesman Gunnar Wortmann said there were "three explosions near the team bus as they left the hotel to go to the stadium".
He added that "there was one player injured inside and damage to a window".
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