The squirrel started its journey by climbing the protective netting behind home plate, and then walked along the wire holding the screen in place above the home dugout. Fans "oohed" and "aahed" as the squirrel impersonated a circus tightrope walker.
The scene went from comic to bizarre -- and even a little scary -- when the squirrel plummeted roughly 30 feet and fell on top of the Phillies dugout to groans from the crowd. The panicked squirrel then lunged into the Phillies dugout, and players scattered to get out of the way. Philadelphia outfielder Odubel Herrera was closest to the squirrel and appeared to make some contact with the animal as it entered the dugout.
The squirrel scampered through the dugout as players and other personnel moved quickly out of the way, but it didn't re-enter the field.
It's unclear where the squirrel went, but it appeared to find a hole under the photographer's well.
The Cardinals have had critters of their own in the past. Several years ago, a squirrel darted across home plate during a playoff game at Busch Stadium.
The Phillies were routed by the Cards 12-4, falling to an MLB-worst 23-46.
Information from The Associated Press was used in this report.