There have been reports the former Manchester City forward is unsettled in his native Italy amid intense media scrutiny and there are suggestions he could return to the Premier League, with Tottenham linked last week.
Mourinho has now hinted that Chelsea could step in and make a bid for the 23-year-old Italy international.
"In football you never know the future," Mourinho told Yahoo.
"Balotelli is with a big club at the moment but you never know the future.
"They want to keep the best players and want to keep the best Italian players. But Mario has already been in English football before.
"I'm not going to be manager of Milan or the Italy national team, but he's a good kid and somebody I'd like to work with again."
Balotelli has previously claimed he would like work with Mourinho again.
"Of course I would like to play under Jose again," Balotelli said earlier this year.
"In my first days at Inter we had some problems, but then it turned into a mutual respect, and now we have a real friendship.
"It is never boring playing under Jose. When you are in Mourinho's team it is a family and he coaches on the principle that if all is well with the family it doesn't matter what is going on outside the team."
Balotelli scored 30 goals in 80 matches during his spell in the Premier League with City, which ended in 2013 when he joined Milan.
Mourinho, who endured a tempestuous relationship with Balotelli during their time at Inter, has complained of a lack of killer instinct from his strikers this season.
Chelsea are currently top of the Premier League but have scored 21 goals fewer than second-placed Liverpool.