Doshi is the all-time leading wicket taker in Twenty20 with 53 victims

Doshi, 28, said: "I didn't feel that I had the backing I should have had."

Doshi has taken 53 Twenty20 wickets from 34 matches, but the resurgence of Chris Schofield has restricted his chances in other forms of the game.

"It's not unusual for sportsmen to be left out. They don't enjoy it but on most occasions fight to regain their place," said Surrey boss Alan Butcher.

"It's a pity Nayan's unwilling to do this. He was part of our future plans."

Slow left-armer Doshi, son of former Indian spinner Dilip, signed a two-year deal with the club at the end of 2006.

He said: "There are no bad feelings as this was my decision and I wish the club the best of luck for the remainder of the season."

Butcher added that Surrey had accepted his resignation and wished him all the best for future.