Zenit St Petersburg have sacked coach Luciano Spalletti with the club lying second in the Russian Premier League.
Chris Powell has been sacked by Championship strugglers Charlton less than a week after agreeing a new deal.
Sunderland manager Martin O'Neill has emphasised his determination to keep forward Stephane Sessegnon at the club.
The 26-year-old was the Black Cats' joint top scorer with eight goals in the campaign just gone and was named their player of the season.
Speculation has begun about clubs being interested in the Benin international, but O'Neill has no plans to cash in on one of his prized assets.
"You can never tell what's going to happen over the summer and I don't want to be saying anything categorically at the start of it which will make us look foolish at the end of it," he told the Sunderland Echo.
"I don't want to say something now which will be thrown back at me next season with people saying: 'Well you said this, or you said that'.
"But there's no doubt Stephane Sessegnon is a player that we obviously want to keep and we'll be doing everything we can to do so.
"He adds something to our attack that no other player does and our priority is to improve ourselves as an attacking force next season.
"If you want to do that, you have to look at keeping your best attacking players and attracting others.
"Stephane has been making the right noises about being happy to stay at Sunderland and hopefully that will be the case."