The keeper lost his place in the starting line-up earlier this season after a run of poor form, but is now back in favour and playing a key role in the club's title charge
The England international was dropped in favour of Costel Pantilimon late last year before eventually regaining his place in the Chilean coach's starting XI.
With the World Cup on the horizon, there had been initial fears that Hart might be usurped as the Three Lions' No.1 for Brazil 2014, but Pellegrini says the goalkeeper has proved his enduring class during the Premier League title run-in.
"The second round of [the season] for Joe has been a very good performance," the former Malaga boss told The Manchester Evening News.
"One of the good things that we did this year was to talk to him and sit him [out] some games because he was in a very bad moment but he reacted as a professional player, the number one in England."