India have already lost the series by losing two consecutive matches. If they make one more mistake it will be whitewash. Which could be a dark chapter for India. So I think it is logical that they should be reorganize around the upcoming match. Spin ball will be effective. The way Shakib Al Hasan is getting wickets can be something like that even if India brings a spinner in the team. But there is no alternative for India to win the next match.
I don't know whether the Indians will be a lot worried about getting whitewashed. They came to Bangladesh without much preparations and refused to play any warmup matches. And in the first match itself, there was no urgency from the part of the Indian batsmen despite losing wickets regularly. They were not serious about their opponents and thought that it will be a cakewalk. And they hardly learnt any lessons from the first match. Even in the second match they showed no seriousness and let the match drift away from their control.