Hamilton is moving from McLaren to Mercedes for 2013, to be replaced at the famous British by Sauber's Perez.
Mexican Perez was sidelined in morning practice in India early on Friday, ostensibly due to a heavy cold. He was replaced by Esteban Gutierrez, who is tipped to move into Perez's race seat full-time next year.
Perez has told Argentine Fox television, however, that he was well enough to drive.
"I am pleased that they are so worried about me," Perez said ironically.
"It's obvious that I'm not 100 per cent, but I've driven in worse shape. There was no reason for me not to drive. I was ready."
Perez said his countryman Gutierrez "did a good job" in the practice session, but insisted: "I would prefer to have done the laps in the car. So we've lost a session.
"Now it's more difficult to set up the car for the race."
Briton Hamilton also looks to be out of favour at McLaren, with the team's sporting director Sam Michael openly telling reporters that the 2008 world champion's car was on Friday fitted with some experimental parts for 2013.
But when asked about the new parts after Friday's track action, Hamilton furrowed his brow and answered: "No, we don't have anything new."