Out of this, Imran Tahir and Ravindra Jadeja seems to be confirmed slots and others may get a chance only if someone out of these two gets injured. And the 3rd choice is going to be Mitchell Santner, and not Chawla (since his batting skills are better). I don't understand the point in splurging almost $1 million on a player, who may not get a single game during the whole tournament.
I think Dhoni have different game plans for this season because CSK bought only bowlers in the bidding action it seems to Dhoni understand the other teams strength and what CSK need exactly.