LEIGH Montagna's wife might have inadvertently revealed her husband's retirement plans on Instagram.

Erinn Montagna posted a photo of her husband Leigh and retiring Saint Nick Riewoldt on Instagram ahead of the duo's Mad Monday celebrations.

She captioned the photo "Awww, these two top guns last ever Mad Monday! We will see you on Wednesday".

But any such revelation was news to St Kilda coach Alan Richardson, who said he was yet to sit down with Montagna for his end-of-season exit interview.

"'Joey' [Montagna] hasn't spoken to me yet," Richardson told Fox Footy on Monday night.

"Joey and I will catch up in the next couple of days.

"Erinn, she might've given him up."

Given Riewoldt has already retired, she may have been referring to the fact it will be their last ever Mad Monday together.

Mrs Montagna amended her post later on Monday, adding the word 'together' in a bid to restore some mystery to her husband's playing future.

But with Montagna's contract status still unknown, there remains possibility she may have accidentally spilt the beans.

Montagna remained tight-lipped when approached by Channel Seven, saying it was "potentially" his last Mad Monday.

"It might be the last one so we've just got to enjoy it and make the most of it," Montagna said.

"I'll make a decision probably in the next week.

"I don't have to rush it so I'll have a little bit more of a thought, but it could be (the last) so I'll make sure we enjoy it with my old mate (Riewoldt) and have a good day."