Paolo Di Canio launched an angry attack on the discipline of his squad after Phil Bardsley was pictured laying on the floor of a casino covered in Â£50 notes.
Bardsley was left out of Sunderland's squad for Sunday's game at Tottenham after the picture of him - taken after Sunderland's survival was assured on Tuesday night following Wigan's loss at Arsenal - was printed in The People newspaper. Di Canio claims the mentality he has encountered at Sunderland is worse than that of previous club Swindon.
"I saw the picture on a website and moments later he was out of my squad," Di Canio, who fined Bardsley and Matthew Kilgallon for the incident, told a press conference.
"How can I play a player that probably is blurry for three, four days after what's happened? I want to deliver a very clear message: there is no excuse to behave like he did. They went out because Wigan lost the game and we stay up. I could understand it if we had won the Champions League or maybe the FA Cup. We have to respect the dignity of the club, and the fans.
"I thought that at Swindon. arrogant, ignorant footballers because they've not had many chances to stay at the top level. I have to tell you unfortunately I found a worse environment in terms of discipline in this club. This is what I've found in the last few weeks so we have to change completely."
Di Canio said he will consider the future of both players after the incident. The image of Bardsley, laying out on the floor amid swathes of cash caused outrage among fans who struggle to cobble enough money to attend matches. Surprisingly, Di Canio has continued to encounter problems with some members of his squad since Tuesday.
The Italian claimed that one squad member who was left out of his squad for Sunday's game refused to train back up at Sunderland's base. The player in question claimed he had food poisoning, but Di Canio does not appear to believe him.
"Some player that couldn't involve (himself) in my squad for a different reason decided: I don't train," the Sunderland boss said, slamming the table. "They make that diagnosis. He didn't go to the Academy of Light because he said 'yesterday I had poisoned food, sorry'. The doctor tried to contact him. His phone was switched off for three hours. This is the situation at Sunderland."
Di Canio revealed earlier this week that he had fined seven players for indiscipline and he also angrily threatened to cut the squad's holiday short because of his disappointment with them. Another outburst against his players may be ill-advised in some people's eyes, but Di Canio insists he needs to take this action if he is to move Sunderland forward next season.
"Maybe I tell you this and they sack me? I don't know but if you want to change something you have to follow me," he said. "These players will not be here next year. Not under me. The owner and I are going to sit at the table and go through but he knows many things. I spoke to him before by telephone and he told me we are going to change many things."