Speaking to ESPN 1000 in Chicago on Wednesday, Rizzo was critical of Montero's decision to go through the media to vent his frustration.
"It's his second time barking at the media and not just going to his teammates," Rizzo said, via John Silver of the Chicago Sun-Times. "As a veteran like he is, you'd think he'd make smart decisions about it. We win as a team and we lose at a team. When you start pointing fingers, I think that labels you as a selfish player."
"It really sucked because the stolen base goes on me. When you really look at it, the pitcher doesn't give me any time. It's like, 'Oh, yeah, Miggy can't throw anybody out.' Yeah, but my pitchers don't hold anybody on. It's tough. ... I don't get a chance to throw. That's the reason they were running left and right. They knew he was slow to the plate, simple as that."
In addition to allowing seven stolen bases, Montero committed an error on a missed throw that allowed Michael Taylor to score after he stole third base.
Montero is just 1-for-31 throwing out base stealers this season after going 7-for-59 last year. ESPN's Jesse Rogers noted Montero's average pop time of 2.11 seconds is the second-worst among all Major League Baseball catchers this season.
The Cubs are having a frustrating year after winning a World Series in 2016. They enter play Wednesday 39-38 but are just one game behind the Milwaukee Brewers in the National League Central.