The 22-year-old was selected ahead of the out-of-form Kieswetter for England's five-wicket defeat to India in Mohali on Wednesday, which saw the hosts complete a series victory.
Buttler, who is a teammate of Kieswetter at Somerset, admitted that he did not anticipate being selected for the match.
"My keeping is still a work in progress, but I think that will improve as time goes on, especially with the amount of work I'm putting into it," thesportreview.com quotes Buttler as saying.
"I didn't really see wicketkeeping coming, but I've been working hard on it before Christmas and also on this trip with Bruce French.
"It's something I think I'm developing and something I think can become a strength of mine."
England face India in the fifth one-day international in Dharamsala on Sunday.