The schedule for both the American League and National League Championship Series could be altered because of the forecast of heavy rain in New York on Wednesday, sources told ESPN.

With the possibility that Wednesday's ALCS Game 4 between the Houston Astros and New York Yankees is a rainout, Major League Baseball is considering moving a potential NLCS Game 5 between the Washington Nationals and St. Louis Cardinals to that night, sources said. The NLCS game is currently scheduled to start at 4:08 p.m. ET, but on days there is only one game, MLB prefers to have the game in prime time.

If the rainout occurs, the Yankees and Astros -- who play Game 3 on Tuesday in New York with the series tied at 1-1 -- would be rescheduled to play Games 4 and 5 on Thursday and Friday in New York, before returning to Houston for a potential Game 6 on Saturday.

Sources said MLB would likely announce any change in an NLCS Game 5 prior to Wednesday, giving the teams and fans time to adjust. The Nationals lead the series 3-0 after beating the Cardinals 8-1 on Monday night, so that series could be over as soon as Tuesday night.

If the Yankees and Astros are delayed a day, it could affect pitching plans for both teams. The Astros could bring back Zack Greinke for Game 4 on regular rest, and the Yankees -- who are planning a bullpen day for Game 4 -- could instead go back to Masahiro Tanaka on regular rest.