Peru striker Claudio Pizarro is being investigated by the German Football Federation (DFB) after television replays showed the Werder Bremen star slap Hanover's Emanuel Pogatetz in the face.
Pizarro scored Bremen's opening goal in their 3-0 win over Hanover in the Bundesliga on Sunday, but got involved in a tussle with Austria defender Pogatetz just after the break.
Referee Christian Dingert did not punish the slap from Pizarro, but the DFB's disciplinary committee has launched an investigation.
The Peru star has been in trouble with the DFB in the past and could be banned for several weeks if found guilty of unsporting conduct, despite apologising for the incident.
"I wanted to get his hand away and I just gave him a little swat," said the South American, who, along with Pogatetz, will have to give a statement to the DFB.
This is not the first time Pizarro has shown some hot-headed behaviour after he elbowed Bayern Munich defender Holger Badstuber in the face during a Bundesliga game last December.