Mumbai Indians now have two wins and five losses from a total of 7 matches. I don't think that they will be able to qualify for the play-offs until some miracle occurs. My prediction for the play-offs is as following: CSK, SRH, KXIP, and RR.
I think RR will be replaced by DD.DD will be doing good from now on; I hope so.
Did you realized that DD is currently on the last position, with two wins from their seven matches? Their net run rate is also lower than all the other teams. Today they are having a match against CSK. If they lose that one, then they will be having zero chances for qualifying for the playoffs.