And yesterday he threatened that players could be punished with fines if they continue to make public their criticism of his decisions.
Brian Laudrup, the talented Danish midfielder, was quoted on Monday for the second time already this season that he was unhappy at being left out of the team. But although Vialli has accepted Laudrup's explanation that the quotes came from an old interview, the Italian is determined to end any public dissension from his cosmopolitan squad.
"It's up to the players to sort it out as soon as possible without me being too hard with them," Vialli said ahead of his side's Cup-Winners' Cup match with Copenhagen tomorrow.
"But of course if nothing is going to change in the future I have to change something to protect the team spirit. Not to protect myself, because I can handle all the criticism and the pressure.
"If we don't change soon, I'll make the players change. I will explain to them it's wrong to do something that's bad for the team spirit. To complain is understandable, but to complain publicly is wrong. I don't want to think now [about fines] because that is another step. The first step is to see if everything gets quiet and nice but if it doesn't I'll find something to make it stop."
Vialli feels he is finally getting through to the team - who are unbeaten since the opening day defeat by Coventry - that public complaints about not being picked are damaging to team morale. The former Juventus striker believes Laudrup is much happier now at Stamford Bridge after playing the last three League games and looking close to getting back to the form he showed for Rangers.
"I think the players know and in the last two or three weeks I haven't read any complaints or any article about players' frustrations. After a while all the players have settled," Vialli added.
"Brian has explained that was a very old interview, about five or six weeks ago when the situation was different. He was still unsure about his position in the team but now he knows I consider him a decisive player and it's in my interests to play him as much as possible. He can do a great job for Chelsea.
"I hope the players understand now. At the beginning we did something wrong, giving you something bad to write about Chelsea because we were making complaints.
"In my opinion everything should be kept in the dressing-room rather than go outside and say something's wrong. Players are allowed to have their say but the most important thing is to be always positive and it's silly to make life more difficult than it already is at the moment.
"To play football and win matches is difficult so it's better to keep the atmosphere always positive. Having said that I understand the players' frustrations sometimes but I think it would be easier for everybody if nothing came out especially in the newspapers.
"The only way journalists can write something wrong about Chelsea should be if we don't get results. Unfortunately I see we are getting results at the moment but you can still write something bad because we give you something to write and that is wrong."
The 34-year-old speaks from personal experience of the situation when he often found himself on the bench during Ruud Gullit's reign as Chelsea manager. He now finds himself with a better understanding of the problems Gullit faced in keeping a large squad of players happy.Reuse content