Mourinho, who left Stamford Bridge in abrupt fashion six years ago, has yet to reveal his hand but even Sir Alex Ferguson has said he expects his old rival to quit Real Madrid and be back in London come August.
Chelsea's interim coach Benitez, speaking ahead of the Sky Live game against Tottenham on Wednesday, hinted that he too knows who his successor will be.
"We know next year there will be a new manager here, so it is very clear. I think everyone knows who will be here," he said.
"I have to concentrate on my job, it is not my concern what will happen here next year. I am doing a good job and I'm sure most of the fans appreciate that.
"What I find every day is a very good group of players, keen to learn. You could see a lot of improvement this year."
After Real Madrid's Champions League semi-final defeat by Bayern, Mourinho had suggested that a return to the Premier League was a distinct possibility.
"I know in England I am loved," he said. "I know I am loved by some clubs, especially one."
As to the Tottenham fixture, Benitez was under no illusion as to the size of the task awaiting his side.
"It is a crucial game; if we win we will be in the top four, nearly guaranteed," he added. "We have had a lot of important games during the season, but this is obviously the most important."