SL players might be not in good form, but they are unpredictable. They many times became lethal against many powerful teams. Currently the bowling side is strong but they do need a good batting lineup as well to give a good fight in their upcoming series.
It is hard to imagine that the current Srilankan team will pose any threat to a strong team like India unless they plan to rest their top international players and book a second class team to face them,they lack in batting power and they have a good team in the T20 format of the game,other than that it will be a one sided series.