CHICAGO – The Chicago Cubs beat the Cincinnati Reds 1-0 on Monday night. Here’s a quick look at the game.

How it happened: Anthony Rizzo hit a walk-off home run off Pedro Villarreal in the ninth inning on a chilly night on which neither team mustered much offense. Rizzo led the frame with his 31st homer of the season to center field, then he was mobbed by teammates at home plate. Travis Wood pitched six scoreless innings and gave up just three hits, and the bullpen finished the shutout. Alfredo Simon was just as good for Cincinnati, as he lasted seven innings and gave up five hits.

What it means: Rizzo returned to the lineup in dramatic fashion, as he played for the first time after missing 18 games with a back injury. He hit his 30th home run Aug. 26, in the game in which he suffered the injury, and almost three weeks later, he hit a no-doubter for his 31st.

Jackson update: Before the game, Cubs manager Rick Renteria said pitcher Edwin Jackson was close to returning from a right latissimus strain. The plan was for the right-hander to pitch a simulated game, then possibly get one or two starts before the end of the month.

Minor affiliates: General manager Jed Hoyer confirmed the Cubs have terminated agreements with three of their minor league Class A affiliates, including the Midwest League champion Kane County Cougars. Agreements with short-season Boise of the Northwest League and Daytona of the Florida State League have also ended.

“You have to do that to look around,” Hoyer said. “There’s no other way to do that process.”

Starting Tuesday, the Cubs are free to explore other affiliate opportunities. They could also return to those franchises.

What’s next: Game 2 of the series is scheduled for 7:05 p.m. CT Tuesday, with Jake Arrieta (8-5, 2.82 ERA) to oppose Johnny Cueto (18-8, 2.15).