MADRID, Dec 6 (Reuters) - Real Sociedad's Brazilian defender Adriano Rossato will have surgery on a collapsed right cheekbone on Wednesday after a fight during training with team mate Juanito.

The two defenders had to be separated by other squad members after exchanging blows at the Basque club's training ground earlier in the day.

'It has been a regrettable incident. Sometimes you lose your head in the heat of the moment and end up ashamed of yourself,' Juanito told a news conference.

'I have put my foot in it and everyone deserves an apology for the bad example we have set.'

Real Sociedad are 19th in the 20-team Primera Liga and have yet to win a game this season. On Saturday they play league leaders Barcelona at the Nou Camp.