"It is very difficult for me to comment on his fitness sitting over here. We have to understand that five-day format has its own uncertainties unlike ODIs or T20s. In ODIs, you know that you have to field for 50 overs only, while in Test cricket there may be a situation that a team might bat for one-and-a-half to two days.

"We have to assess whether Yuvraj is ready to field for two days," Dhoni replied to a query on whether Yuvraj is fit enough to be selected for the Test series against England.

"Having said that it is Yuvraj who is the best judge about how he is feeling. He has played quite a few domestic games now and it is up to him to reflect on his game," the Indian skipper told the media persons during a promotional event here today.

Dhoni also spoke on the same lines as his colleagues Harbhajan Singh and Virat Kohli, with his vote going in favour of the turning tracks.

"I still believe that the groundsmen know what really is good for us. Sporting track always doesn't mean that it will only have grass on it. In the sub-continent it has always been turning tracks, which is for the spinners.

"I haven't seen an off break bowler for a long time who is able to hit the rib cage of a batsman with a delivery that has turn and bounce. It's really painful but you enjoy the challenge," said Dhoni.

England Test series is being sought as a revenge series but Dhoni didn't want to predict the outcome.

"I don't believe in predicting results. I know that we need to train hard and also look into specific areas."