Pietersen, 32, was dropped from the England team for sending "provocative" texts messages to South African players but made his return to the team in a warm-up match against India A at the Brabourne Stadium.
"It's pretty much business as usual. I don't suppose you'd be able to see from the outside looking in ... that it's anything than normal. There's nothing exceptionally different. He's the same old Kev - energy in the field that he showed today, all day," the Telegraph quoted Bresnan, as saying.
"Everyone in the know has sat down and spoken about it. But apart from that, for the rest of the boys, I guess it's just like having someone who's been injured coming back into the side," he added.
According to the paper, Pietersen took a catch to give Bresnan the first of three wickets as India A closed on 369-9.
England also had to deal with losing paceman Steven Finn to a suspected thigh injury, who left the field during his second spell, the paper said.
"I'm pretty sure most of the lads in the dressing room were expecting it to be like that, and that's what it was like. For the lads, it's nothing different to having [any] player come back into the squad who's been missing for a while," Bresnan said. (ANI)