Both players left the Camp Nou this summer - Fabregas for Chelsea in a £27m transfer, while Tello moved to Porto on loan - and the winger has said that his former teammate should have been given a better send-off by his boyhood club.
"Cesc didn't leave Barca how he deserved," Tello is quoted as saying by Marca. "He left seemingly through the back door.
"He has been a spectacular player, you just have to see the goals and assists that he provided.
"I guess he is still hurt because it was his dream to triumph at Barca. I don't know why the fans didn't take to him."
Fabregas scored 28 goals in 96 appearances during his three-year spell at Barca.