Kanpur: India were grappling with a new selection headache on Saturday, with in-form opener Gautam Gambhir opting out of the crucial third Test against Sri Lanka in Mumbai.

Gambhir has been given permission by the Indian cricket board to attend his sister's wedding, which falls on the second day of the Test opening at the Brabourne stadium on Wednesday.

Gambhir's absence is likely to throw India on the back foot as they seek to win the three-Test series, which they lead 1-0 after their innings and 144 runs victory in the second match on Friday.

The opening Test in Ahmedabad ended in a draw.

A 2-0 series win will put India on the top of the Test rankings and also deny Kumar Sangakkara's men their maiden victory on Indian soil in the longest version of the game.

Gambhir, 28, has been enjoying a golden run with the bat, having hit four centuries in a row in his last four Tests, including knocks of 114 and 167 in the current series.

It was his vital 233-run opening partnership with Virender Sehwag in the second Test which laid the platform for India's massive victory.

In his last 25 innings, Gambhir has hammered seven centuries and seven half-centuries for a stunning average of 77. Overall, he has scored 2,553 runs from 27 Tests since making his debut in 2004.

India's captain Mahendra Singh Dhoni was measured in his response when asked about Gambhir's unavailability.

The Indians have a reserve opener in their squad in Murali Vijay, who has played only one Test, against Australia in November last year.

But India could promote current number three Rahul Dravid to the opener's slot and include an extra bowler in place of Gambhir, considering the bowler-friendly pitches of Mumbai.

Dravid, a veteran of 136 Tests, has opened the innings on 18 occasions and notched up an average of 32.60.

However, at his favourite number three position, Dravid averages a neat 55.23.

With Sehwag in fine nick at one end, the onus will be on the new opener to adjust to his hard-hitting ways, something that his Delhi teammate Gambhir is used to.