The 47-year-old - whose infamous 'Hand of God' goal knocked England out of the 1986 World Cup in Mexico - spent some time chatting to Blues manager Avram Grant as well as Michael Ballack, striker Andriy Shevchenko and Chelsea's new Argentinian youngster Franco Di Santo.
"In the world of football he is a hero for every player, he is an incredible player," said Shevchenko, who has returned to training following a back problem.
"He is a legend, a hero for everyone, and a fantastic player. He has had a difficult life, but he is doing well now. His look is good and it's important for him.
"He has lost a lot of weight, and feels much better."