Pellegrini was still injured at the start of the season, and ultimately missed the first match. He was benched for the second and third matches, so his performance remains to be seen. But yeah, some people also relate gasperini decision on Pallegri absent in several matches on bench. However, when he received his first appearance, he immediately scored. Similarly, in this match against Nice in the UEFA Champions League, Pellegrini provided an assist for Evan Ndicka's goal. So, his contribution to AS Roma has been quite significant.
Pellegrini is not a great player like Totti or De Rossi but he is a captain of AS Roma in most successful era of this club history in UEFA leagues from Conference League to Europa League. He was not only AS Roma captain in those seasons when they won UEFA Confererence League, had a UEFA Europa League final match and one season after that they went to semi finals in Europa League too, but he actually had great contributions for the club in these impressive seasons in Europe.
His contributions for the club are marked in the club history but player career has up and down, and with time, they get older, have less contributions and will have to leave the club or retire. I know Pellegrini still can contribute many things for Roma and hopefully the conflict with Gasperini (if exists), will end soon.