Indian captain Sourav Ganguly remains doubtful for the first Test against Pakistan starting on Sunday even though MRI scans have shown that his back injury is not serious, the team manager Professor Ratnakar Shetty said.

Ganguly sustained the injury when he fell awkwardly while fielding in the fifth and final one-day international on Wednesday, which India won by 40 runs to clinch the series 3-2.

"After the MRI scans, it has become clear that Sourav has no serious injury," Shetty told reporters on Friday.

"He only has muscular pain and the team physio is treating him. But it's early to say if he will be able to play in the first Test. We might a clearer picture tomorrow after a few sessions of therapy."

Ganguly could be replaced in the team by left-hander Yuvraj Singh, whose only previous Test was against New Zealand in Mohali last year, when Ganguly was out with a groin injury.