St Kilda are backing star AFL defender Sam Fisher, who is pressing charges over an assault outside a city nightclub.

Fisher, the Saints' 2008 best and fairest, suffered a cut to the back of the head and needed stitches after the Saturday night attack.

He was leaving the nightclub and said a stranger struck him.

The club called the incident "an unprovoked attack".

Saints president Greg Westaway said he was satisfied Fisher had done nothing wrong.

"That's the question I asked - I said 'are we sure about this?'" Westaway told Radio SEN.

"They said 'totally unprovoked, we have got witnesses' and Sam feels that miffed about it, he's going to press charges.

"A witness said they thought they saw something in the hand of the assailant."

Westaway also defended the right of footballers to have a social life.

"It's pretty hard to draw a long bow at this, but these guys are entitled to have a life outside of footy and they're entitled to be able to feel safe when they go out," he said.

"We can't say to them 'you're never to go to a nightclub, you're never to go out of a night time and enjoy yourself' - we wouldn't have too many players playing for us."

The Saints added that Fisher did not retaliate and let venue security know about the attack before going home.

They said the backman reported the incident to police on Tuesday, but was yet to make a formal statement.

Fisher, who missed Saturday night's practice match loss to Sydney after copping a knock to the face in a NAB Cup game, will still be fit to play in round one.

The Saints play Geelong at the MCG on Friday week.

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