There have been 26 weather-related postponements this season, and according to The Associated Press, that's the most through April since Major League Baseball began keeping records in 1986.
There were 26 postponements through April in 2007, but one was in response to the death of St. Louis pitcher Josh Hancock.
Sunday's game will be played May 28 at 7:10 p.m. ET as part of a day-night doubleheader.
Rain began falling at SunTrust Park late Sunday morning and was forecast to continue through the afternoon and night.
Right-hander Mike Foltynewicz, who was scheduled to start for the Braves, will have his start pushed back to Monday night, when Atlanta opens a four-game series at Cincinnati. Braves manager Brian Snitker said no starter will be skipped; others in the rotation also will be pushed back one day.
The Mets also will push back their scheduled starting pitcher, Zack Wheeler, to Tuesday night, when New York opens a three-game series at St. Louis. The Mets are off Monday.
Right-hander Noah Syndergaard will start against the Cardinals on Wednesday, filling the rotation spot originally planned for Matt Harvey. The Mets announced on Saturday that Harvey, struggling with a 6.00 ERA, is moving to the bullpen.
The unscheduled day off was well-timed for at least two Mets players.
Callaway said Frazier "got spiked pretty good'' at third base on Saturday night and his toe was "throbbing pretty good.''
Bruce was 2-for-12 in the first three games of the series and is hitting only .194 this season with one homer.
"We decided before the game [Saturday] we were going to give him a day off so he could have two in a row,'' Callaway said of Bruce. "Just let him relax a little bit for a couple days.''
The Associated Press contributed to this report.