The Senegal international was dropped from the starting line-up at Norwich last weekend for arriving late to a team meeting, although he was brought on for the final 10 minutes of the 1-0 defeat.
Mane was subsequently linked with a move away from St Mary's during this month's transfer window, Manchester United again the reported suitors after they targeted him in the off-season.
"What happened last week, it gave the press something to write about," the Dutchman said. "Sadio's situation is no different to last week. He is a Southampton player, he likes to play for Southampton, he is not for sale.
"We spoke to him. I punished him because we have rules in the team and he was late, it was a big mistake. He said sorry to everybody and that's now behind us.
"The rest is just internal discussions about how we handle this kind of situation. He will start Saturday no problem.
"It's too easy to mention after the mistake of Sadio or Victor to say they want to move. That's too easy. It's not like that. The players know their position in the club and what we think of the players, I don't have doubt about that."