Mason Mount, Lewis Hall, Ruben Loftus-Cheek, Ian Maatsen, Callum Hudson-Odoi and Billy Gilmour are among players who grew up at Chelsea and then were sold. Conor Gallagher is set to be the next at Atletico Madrid.
Asked if the Blues risk upsetting fans by selling popular youth players, Maresca said: "But this is not Chelsea's problem, these are the rules. All clubs at the moment are forced to sell players of the academy because of the rules.
"They are problems of all the Premier League clubs. It's not just us.
"It's a shame because in Italy we have Francesco Totti who stayed at Roma for 20 years, a man who now represents the Giallorossi club seeing this in football, the fans want to see it, but with today's rules it is different than in the past."