Nicklas Bendtner was reported to the police by a Copenhagen taxi driver who claims the Danish striker was behind a violent attack early on Sunday.
The taxi driver had undergone surgery for a broken jaw, a spokesman for taxi firm Dantaxa told Reuters.
Danish newspaper Ekstra Bladet cited unnamed sources saying Bendtner was arrested early on Sunday, charged with violence, but later released by the police.
Bendtner plays for Norwegian side Rosenborg but was not picked for the Denmark team that hosted Wales in a UEFA Nations League match in Aarhus.
A spokesman for Copenhagen police said there had been a number of reported cases during the night involving violence against taxi drivers, but he declined to comment on individual cases.
A spokesman for Rosenborg declined to comment and the Danish Football Association (DBU) also declined to comment. Bendtner could not be reached for comment.
Bendtner, who was left out of the Denmark side that reached the knockout phase of the World Cup in Russia this year, burst on to the scene in 2005 as a precocious talent at Arsenal, but was soon on loan to Birmingham City.
He went on to represent Sunderland, Juventus, Wolfsburg and Nottingham Forest but his goals were often overshadowed by tabloid tales of drink-fuelled escapades.
After signing for Rosenborg, Bendtner has started to rediscover his best form, winning the Norwegian title in 2017. This season he has scored five goals in 17 league matches.