Spaniard Pedro de la Rosa will replace Juan Pablo Montoya at McLaren for the rest of the season after the Colombian announced he was leaving Formula One for NASCAR, the team said on Tuesday.
"Team McLaren Mercedes and Juan Pablo Montoya have mutually agreed for him to step down in the forthcoming races of this year's Formula One World Championship," McLaren said in a statement.
"The team has decided that Pedro de la Rosa will join Kimi Raikkonen in the race driver line-up."
Montoya took Formula One by surprise on Sunday when he turned up in Chicago to announce that he was moving to the US Stock Car series in a team run by Chip Ganassi, with whom he won the CART championship and Indy 500 in 1999 and 2000.
The decision means Montoya's final appearance in Formula One will be his dismal showing in the US Grand Prix at Indianapolis earlier this month rather than this weekend's French Grand Prix at Magny Cours.
Montoya, who won four races with Williams and three with McLaren, collided with Finnish teammate Raikkonen at the first corner at Indianapolis.
The Colombian sounded like he had already mentally made the leap to NASCAR on Sunday when he said of Formula One that, "Anyone who watches the races knows its not the most exciting thing you can watch.
"How hard is it to pass a car in Formula One? You pass them and you touch wheels and you're an animal," he said in a news conference.
McLaren said the mercurial 30-year-old, whose wife Connie is expecting their second child, would now spend the next few months in Miami while making initial preparations for his debut in Ganassi's Dodge.
"Juan Pablo is an exciting driver and immensely likeable character who will undoubtedly make a successful transition to the NASCAR scene," McLaren team boss Ron Dennis said.
"We have agreed that with so many things happening in Juan Pablo's life right now, he should take some time out of the car and prepare professionally and personally for the future."
Magny-Cours will see De La Rosa, the team's regular test driver, make his second race appearance for McLaren after standing in for the injured Montoya in Bahrain last year.
De la Rosa, a former Arrows and Jaguar driver before joining McLaren, finished a strong fifth in that race and will be eager to show his pace with the team yet to confirm their second driver for 2007.
McLaren have already signed Spanish world champion Fernando Alonso from Renault for next year but Raikkonen is expected to leave for Ferrari or Renault.
"I'm of course extremely thrilled to have this opportunity to race the MP4-21 -- a car in which I'm really comfortable," De la Rosa said.
"I know the MP4-21 better than anyone else and I'm confident that I can achieve important World Championship points for the team," he added.