Sourav Ganguly will have to undergo a bone scan before he is cleared to play in the fourth Test in Mumbai, beginning on November 3.

"He is out due to a strain in the right thigh. We still haven't been able to discover what the injury is exactly like, so we cannot say how long he will stay out of the series," India's physiotherapist Andrew Leipus said on Tuesday, after the first day's play in the third Test in Nagpur.

He added that India's captain will have the bone scan on Wednesday.

On Monday, Ganguly had said he felt "fine batting in the nets" and his exclusion from the squad came as a surprise.

Leipus also said Harbhajan Singh was left out of the squad for the Test because he "looked too weak to take field" following a bout of gastroenteritis.