The 27-year-old Powar twisted his ankle during a training session on Monday, and the 23-year-old Sreesanth was still trying to overcome a similar injury that he copped in Abu Dhabi.
"They are both recovering well," remarked Chappell, after India completed a five-wicket victory over West Indies with one ball to spare in the first One-day International on Thursday at Sabina Park.
"Sree should be able to play on Saturday, but Ramesh may need an extra game before we consider him again.
"They have both recovered well quickly, and this is a result of some intensive rehabilitation work over the last few days to which they have responded very well."
Ramesh is a stocky off-spinner, whose lower-order batting has helped fortify India's batting line-up in recent matches, and Sreesanth is an emerging fast bowler with the potential to bowl genuine pace.