The game never began and was called after a 57-minute delay. It wasn't immediately rescheduled.
It was the fourth rain delay in 10 dates this season at Great American Ball Park. One game also was suspended overnight because of rain.
Right-hander Jeff Samardzija was scheduled to face Cincinnati's Alfredo Simon. Samardzija went into the outfield and threw briefly when the game was called.
It was Simon's first scheduled start since an unidentified woman filed a civil lawsuit against him in a Washington, D.C. court last Thursday, claiming he sexually assaulted her in a hotel one year ago.
"I take him at his word that nothing happened and he's assured me that he's ready to pitch and his focus is on pitching," manager Bryan Price said.
Samardzija is trying to break a streak of 11 straight starts without a win since last Aug. 30. Samardzija has pitched well — quality starts his last eight games — but the Cubs have scored only 21 runs while he was on the mound in the last 10 games.
Last Wednesday, Samardzija left with a 5-0 lead before Arizona rallied for a 7-5 win.
NOTES: Cubs RH Jake Arrieta will be activated off the DL and start the final game of the series on Wednesday. He's been sidelined since March 21 with tightness in his pitching shoulder. RH Carlos Villanueva will move into the bullpen. ... RF Nate Schierholtz got a day off. ... Reds RH Mat Latos has resumed throwing. He's been on the DL all season while recovering from knee surgery and stiffness in his forearm. He hopes to get back to throwing off the mound later this week. ... Closer Aroldis Chapman will throw to Reds hitters again on Tuesday. If there are no problems, he'll be sent for a brief rehab stint in the minors. Chapman was hit on the forehead by a line drive on March 19. ... OF Skip Schumaker started a rehab assignment at Triple-A Louisville on Monday. He's recovering from a separated left shoulder suffered during spring training.