Chahal wasn't picked for the T20I series opener versus Australia on Friday.
At the toss, skipper Virat Kohli informed Chahal isn't part of the team for the series opener in Canberra. The 30-year-old wasn't included for the final ODI on Wednesday either after twin failures in the first two games in Sydney.
During a pre-match show for Indian broadcaster 'Sony', Manjrekar said he feels "sorry" for the veteran leggie as the team management mixed formats in taking their decision.
Chahal just recently had his best IPL season in UAE, taking 21 wickets in 15 innings while conceding only 7.08 runs per over. He was instrumental in Royal Challengers Bangalore (RCB) making it through to the play-offs.
"I feel sorry for Chahal," Manjrekar said. "I just feel that it's one of those games where they feel that he is tired, he has played a couple of games and let's rest him."
"Also, the lines are getting blurred between 50 overs and T20s. When you look at Chahal, he has had his best IPL ever as a leg-spinner and in the first game he plays for India, he is dropped."
"Some of the things that are happening because of the number of matches, also he had a couple of rough games in the ODIs, that's a little unfair. He was in such great T20I form but unfortunate to be dropped for the first T20I. I am looking so far ahead. I am just looking at players available and what could be India's best possible XI," he added.
Chahal, without a doubt one of the world's best T20 spinners, has taken 55 wickets in 42 T20Is for India with an economy of 8.18. His IPL record gives an even more impressive reading, with 121 scalps from 99 outings while going at just 7.67 runs per over.
(Inputs from India Today)