I think we can't, Rayudu's place was always fragile in the team, two bad games and he's out!! That's how it had been with most of the No 4 batsman Team India tried in the past 1 year. And as you said, Kedar is prone to injuries, especially hamstring is notorious and it can come back anytime, so he is vulnerable. And as you said Jadeja seems to have lost his steam after making a brilliant come back, but the value he brings to the team with his fielding is unquestionable, he is just BRILLIANT in the field! I don't care if he doesn't bat well, as long as he can bowl economically and save 10-15 runs for the team and gets a run out or two. Today's team was very good sans Shankar. I can't understand why Shankar is playing ahead of Krunal, enlighten me please. And if Hardik is coming back, there is no way Shankar can make it to the final XI.
Based on the condition he's picked bro, instead of Hardik. Already 3 Spinners available so no 4th spinner required. If at all krunal comes in the 15 it shud be in place of jadeja.
Am sure selectors will be keen to try 3rd spinner for the world cup, with jadeja s place not sealed krunal will be a serious contender for 3rd spinner slot & will come as a straight competetor for jadeja.
Feel krunal may be tried @some point in odis in the place of jadeja. Also there's a chance Jadeja may get a nod & Krunal maybe tried after the world cup. Things seems very tight at the moment.