DELHI, Jan 5 (Cricinfo): MS Dhoni's participation in the final One Day International (ODI) against Pakistan is in doubt after he complained of soreness in his back during practice at the Kotla in Delhi.

Wicketkeeper-batsman Dinesh Karthik has been called up as back-up for the Indian captain.

"If at all somebody is doubtful, it's me," Dhoni said when asked about the absence of Yuvraj Singh at the practice session. "Since it was an optional practice session, Yuvraj did not come."

The issue of who will take over the captaincy will come to the fore if Dhoni misses out Sunday. Over the last year, India have had three alternatives: Virender Sehwag when Dhoni was out with over-rate bans in Australia, Virat Kohli was vice-captain in Asia Cup, Gautam Gambhir in Sri Lanka, and now there is no official vice-captain. When asked, Dhoni said, "Let's hope that I play. We'll see tomorrow."

The final decision on Dhoni's fitness will be taken on the morning of the match.

The news will be a setback for the Indian side who have already lost the series to Pakistan, and are looking to avoid their first home ODI series whitewash since 1983-84.

Dhoni was the only India batsman who showed form in the previous two matches. He has scored 167 runs - 106 more than Suresh Raina, who is second - in the series without being dismissed.