"Zaheer will replace Pakistan spinner Saqlain Mushtaq in the Surrey team. The dates (of the matches he has to play) are not fixed yet but Zaheer has agreed to the offer," a source close to the player said on Saturday.
The left-arm seamer, who has been laid low by different injuries in recent times, is currently going through a fitness programme in England.
Zaheer, who missed two Tests in Australia due to a persistent hamstring injury and later returned home midway through the tour of Pakistan, was focussing on regaining his fitness before beginning cricket training, he said.
Being away from the media attention has had a soothing effect on Zaheer who was put off by the negative criticism of his performance during the Pakistan series, the source added.
Zaheer would return to India to attend the fast bowlers' camp in Bangalore in June.