Perez withdraws from Canada GP

Having previously been passed fit by the FIA medical examiners, Sergio Perez returned to his Sauber for yesterday's first practice session.

However the Mexican who is in his first season of Formula One soon felt unwell and told his team he was feeling sick.

Due to the nature of his accident in qualifying at Monaco, the team and driver decided it was best if Perez sat out the race and Pedro de la Rosa will race in his place.

'This development hit us by surprise, because Sergio underwent thorough medical checks, first in the hospital in Monaco, then in a hospital in Zürich, and finally, the FIA doctors gave him the green light this Thursday in Montreal. Nobody could have foreseen that he would feel unwell. Maybe we are being overly cautious, but when it's about the health of our drivers we take zero risks.' Peter Sauber told Autosport Magazine.

Perez suffered concussion from his crash in Monaco and spent two evenings in hospital, missing the Grand Prix, but had insisted that he would be well enough to return to the car this weekend.

'Of course I wanted to drive and I had no doubt I was alright, But apparently this is unfortunately not the case. I am deeply disappointed.' Perez added.

'I spoke to the team after the session and told them that I'm not a hundred per cent fit. I only want to drive when I'm a hundred per cent well. I need some more time to recover.'

McLaren's reserve Pedro de la Rosa was drafted into the car just ten minutes prior to the second practice session getting under way on Friday.

Sauber and McLaren had organised the deal to see the veteran driver race during the week, but following Perez passing his medical de la Rosa was surprised to discover he would be racing after all.

'I was finishing lunch when [Sauber CEO] Monisha Kaltenborn showed up at McLaren and asked me, 'are you ready? It's very likely you will have to get in the car', I checked my watch and it was ten to two and I said 'but there's 10 minutes to the start of the session!'

'From then it was a crazy race to get my helmet, my overalls, my things at McLaren!' de la Rosa said.