CHICAGO (Interstat) — The Arizona Diamondbacks and Chicago Cubs will play a split doubleheader Saturday at Wrigley Field, a day after the Cubs won 6-5 in the series opener. The first game is scheduled for a 1:20 p.m. CDT start; the nightcap will begin at 6:40 p.m. CDT. The forecast calls for 45-degree temperatures and rain, creating a potential for delays or postponements. Arizona (16-15) will send right-hander Ryne Nelson (1-2) to the mound in the afternoon. Left-hander Shota Imanaga (2-2) is the probable starter for the evening game. Chicago (20-12) has not announced its starting pitchers for either game, likely waiting to see how much work the bullpen requires in the doubleheader. The Cubs won Friday behind a strong start from Colin Rea, who is expected to pitch in this series. Rea allowed two earned runs over 5 1/3 innings, striking out six. Over his last four starts, Rea is 3-1 with a 2.40 ERA, including six-inning wins over Philadelphia and Tampa Bay. Diamondbacks shortstop Geraldo Perdomo is a player to watch. In Friday’s loss, Perdomo went 2-for-5 with a home run and three RBIs. He is hitting .357 (5-for-14) with two homers over his last four games, though he had an 0-for-5 stretch in between. Arizona comes to Chicago after losing three of four in Milwaukee, dropping a 13-1 decision Thursday. The Diamondbacks are 4-6 in their last 10 games. The Cubs have won seven of their last 10, including a three-game sweep of Philadelphia and a series win in San Diego. Chicago’s pitching staff has posted a 2.89 ERA over the last week. Interstat’s game simulator projects a 6-4 Cubs victory for the nightcap, but the weather could affect both games. A rainy afternoon would force a later start or a postponement, potentially creating a split doubleheader Sunday — with the teams already scheduled to play Sunday afternoon. The series concludes Sunday. Arizona then returns home to face Pittsburgh, while Chicago hosts Cincinnati. Both teams also have a quick turnaround after this weekend with a trip to Texas later in the week.