Ronny Deila has backed Scott Brown but concedes the Celtic and Scotland captain's midweek antics were "not a positive example" for youngsters.
The midfielder was pictured in one newspaper apparently slumped in the street after a night out in Edinburgh on Wednesday.
Brown, 29, showed no after-effects in Celtic's 2-0 Scottish Cup League Cup final win over Dundee United at Hampden Park, which came courtesy of goals from Kris Commons and substitute James Forrest.
Afterwards, the Celtic boss, who has made known his desire for his players to be "24-hour athletes", said: "It's not a big case.
"He was home at 10.30pm, it looks like he was home at six in the morning.
"Broony has played 60-65 matches this year. He had a day off and wanted to be out with his friends. I have no rules about that.
"I said the players have to be fit and Scott Brown is the fittest player we have but we have a reputation to take care of.
"It's not a positive example for the youngsters. We weren't proud of the pictures and things that appeared in the newspaper.
"We have to learn from this. When you are playing for Celtic everybody is chasing you. You don't get personal time so you have to always know what you are doing.
"But again it is not a big issue. He made up for it today. He had a very good game."
Commons backed his skipper who had a fine game against United, although attacking midfielder Stefan Johansen was named man of the match.
"I wouldn't say he bounced back - Broony does what he does," Commons said. "As a captain and a role model in the dressing room, he is one of a kind.
"As far as man-of-the-match prizes go, he was right up there today. He controlled the match. His energy and drive is second to none."
Deila was asked about one newspaper story linking Liverpool's LA Galaxy-bound captain, Steven Gerrard, with a loan move to Parkhead in 2016.
He said: "It's new for me. It is one year away. I'll take it day by day. Gerrard is a hero, a Liverpool star and best player of all-time. It's a good name. We'll see if it's possible in January."