Michael Appleton has thrown his support behind Liam Lawrence.
The Pompey skipper was cautioned by police for assault on a reveller at Cafe Parfait in Southampton.
Dad-of-two James Thorp was headbutted by the 30-year-old in the December 11 attack.
The Republic of Ireland midfielder, who admitted the offence, has since been disciplined by the Blues internally.
Although, Appleton has ruled out stripping him of the captaincy.
Lawrence is available for the Boxing Day visit to Millwall but a sore hamstring has cast doubt over his involvement.
Regardless, Appleton has accepted it was a one-off mistake from his player.
And the Blues boss has insisted the matter is now closed.
He said: ‘Liam has been punished internally by the football club for his actions.
‘That has gone now, it is out of the way and he knows my feelings on the matter.
‘I have made my thoughts very clear to him about what I thought of the situation.
‘We haven’t stripped him of the captaincy or anything like that.
‘He made an error, he made a mistake and he put his hand up straight away.
‘As far as I am concerned, if Liam continues to make those types of bad judgements and errors then that will need to be addressed.
‘But at the minute – from my point of view – he has made one mistake.
‘The biggest mistake was going out in Southampton.
‘It is actually out of character and quite surprising. I was in a little bit of shock myself when I got the phone call.
‘I have not seen that side of Liam since I’ve been at the football club and I have not heard of him as that sort of character within football.
‘Certain things happen in life sometimes.
‘You regret them and I’m sure he regrets it.
‘It has been dealt with and we move on and try to put a blanket on it.
‘Hopefully we can start talking about what Liam Lawrence is doing on the field rather than off it.’
The Blues are currently sweating on whether Lawrence will be fit for the trip to The Den.
The former Stoke man has a sore hamstring in the aftermath of his comeback match against Southampton.
The problem has so far kept him out of training this week.
And Appleton is wary of making the problem worse by throwing him into the Millwall visit.
He added: ‘Liam was a little bit sore in terms of his hamstring but we’re easing him through it a little bit.
‘We won’t take a risk on him if he is too sore.
‘After being out for five weeks the last thing we want is him coming back for one game and then missing three or four.
‘We will look after him this week and assess him.
‘If he’s ready to play then fine.
‘If he isn’t, we move on to the Leicester game.’