Russian driver Petrov has had his seat fitting completed and will now travel to Barcelona for the second pre-season testing later this week.
"We are all delighted to welcome Vitaly into our team and are very excited about the role he will play in helping us take the next steps forward in 2012 and for many years to come," said team principal Tony Fernandes. "I also want to take this opportunity to thank Jarno for the absolutely pivotal role he played in the formation and progression of our team since he joined us in December 2009.
"Jarno knew that when he joined us it would be a very different environment to where he had been before, and when we gave him the package he wanted he absolutely shone.
"With that in mind it was not an easy decision to bring Vitaly in to replace Jarno, but it was one we made to ensure that we give fresh impetus across the whole team and with a realistic eye on the global economic market."
Petrov has previously driven for Lotus Renault.