AHMEDABAD: India do not boast a mystery spinner like Pakistan's Saeed Ajmal but off-spinner Ravichandran Ashwin's variations make him quite a handful, team captain Mahendra Singh Dhoni said on Wednesday.

The onus will be on India's slow bowlers to exploit England's weakness against spin on bouncing and turning wickets at home in the four-test series starting on Thursday.

Ajmal was the leading wicket-taker with 24 scalps from three tests when Pakistan blanked England 3-0 in the United Arab Emirates at the beginning of the year.

Ashwin has replaced veteran Harbhajan Singh as India's spin spearhead and has been the man of the series in their last two series at home against West Indies and New Zealand.

“I feel they are different bowlers. It's a bit unfair to compare two individuals,” Dhoni said on the eve of the first test in Ahmedabad.

“Ajmal has got a brilliant doosra and generates a lot of pace when it comes to the ball that goes away from a right-handed batsman. He's quite special.

“But Ashwin also has got variations, he has got different deliveries. He can almost bowl each and every delivery that anyone can bowl. He's got the flipper, he bowls leg spin, off-spin, the carom ball.

“The majority of his deliveries are still off-spin. I think it's important for him to concentrate on his stock delivery and use the variations as variations.”

Ashwin, 26, has forged a strong partnership with left-arm spinner Ojha, the duo sharing 73 wickets in the five tests they have played together, and England's chances in the four-test series will depend on how they handle the duo.

“They understand each other really well, something that's very important,” Dhoni said.

“If it's not turning then Ojha is someone who can keep it tight. Ashwin will always be the more aggressive bowler.

“The best part is if there is something for them (in the wicket) they make sure they come into the game.”

The Indian captain confirmed that paceman Ishant Sharma had not recovered fully from viral fever which has ruled him out of Thursday's first test.

The hosts have called up uncapped Ashok Dinda to their squad as cover for Sharma though Zaheer Khan and Umesh Yadav are expected to be the preferred choices from the pace department.