By Steve Keating

MONTREAL (Reuters) - Pedro de la Rosa will return to the Sauber team that sacked him a year ago for Sunday's Canadian Formula One Grand Prix as a fill-in replacement for Mexican rookie Sergio Perez, who pulled out of the race after feeling ill.

De la Rosa, a 40-year-old Spaniard who was dropped by Sauber with five races remaining last season, got the call from his former team just 10 minutes before the start of Friday's afternoon practice session when Perez complained of dizziness.

Perez, who sustained a concussion and bruising in a heavy qualifying crash that ruled him out of last month's Monaco Grand Prix, had posted the 11th best time in morning practice at the Circuit Gilles Villeneuve.

Once that was done, they had to fit De la Rosa into the car and get him on the track before the end of the 90-minute session.

The Spaniard was so rushed that he drove the late practice in his McLaren racing suit, helmet and boots. But he posted the 18th best time in the session, beating six other drivers, including Michael Schumacher.

"Just 10 minutes before the session I was told (to go), if I was ready," said De la Rosa. "After that it was all bang, bang, bang.

"It is the latest call in my whole career but I am extremely happy McLaren has released me and Sauber thought about me to replace Sergio."

In 12 years on the Grand Prix circuit, De la Rosa has worked for four teams, making 85 appearances on the starting grid and earning one podium finish, a second place at the Hungarian Grand Prix of 2006.

"I approach tomorrow with a smile on my face, it's an opportunity I did not expect," said De la Rosa. "I'm just happy to be here.

"I realize I have a lot to learn with all the new buttons that these cars have and they are in completely different positions to what I am use to.

"Today I had a bit of struggle with the pedals but I think what the team did in one hour was outstanding."

Perez said he was disappointed at having to give up the drive but was feeling too unwell to give a proper account of himself.

"I want to get back in the car when I am 100 percent and I discussed with the team we took the position not to risk anything," said Perez. "I was getting a bit dizzy when I was driving and I was very honest with the doctors.

"I am just starting my career and I want to be here many years.

"I want to be 100 percent because my team deserves a driver who is 100 percent.

(Editing by Julian Linden)