Yuvraj Singh's brilliant form in domestic matches has made him a serious contender for a slot in the Test team but Indian captain MS Dhoni is still not sure whether the talented left-hander is ready to face the rigours of five-day cricket.

"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.