Spinner Harbhajan Singh is battling a bout of flu, but remains available for selection ahead of India's third Test against England, which gets underway in Kolkata on Wednesday.

Illness cast Harbhajan's participation in the Eden Gardens clash in doubt, with the veteran missing training on Tuesday, when captain Mahendra Singh Dhoni acknowledged his team-mate's absence.

"Harbhajan is down with flu and he stayed at the hotel and did not come down for the practice. We will have to go back to the hotel and check his condition. Only after assessing his condition, we will take a call," Dhoni told reporters.

However, the 32-year-old Singh has since recovered - if picked he will become the 10th Indian to earn 100 Test caps, including team-mate Virender Sehwag and former captains Sachin Tendulkar, Rahul Dravid, Sourav Ganguly, Anil Kumble, Sunil Gavaskar and Kapil Dev.

"I am fit on this day, but I have been down with flu for the past few days. Since I am recovering from flu, I thought it is better to take take some time to rest away from practice on Tuesday," added Harbhajan.

Meanwhile, Dhoni has rallied behind openers Sehwag and Gautam Gambhir, after a poor performance from the duo at the Wankhede Stadium. The pair shared paltry stands of four and 30 - a stark comparison to England openers Alastair Cook and Nick Compton's 66 and unbroken 58.

"We all know about the ability of our openers. If both of them can score in the same innings it will be a big plus for us. We don't want to put extra pressure on them but back them for the game they are used to play," added the home skipper.