The man wearing Cubs gear and believed to be in his 20s was reaching out over the railing down the left field line attempting to catch foul balls on Sunday when he tumbled headfirst over the rail and onto the hard dirt below.
"Very shaken up, looking around the stadium, there's got to be something to prevent that," Cubs shortstop Ryan Theriot said. "I guess it could happen to anybody going for a ball. Guys get those front-row seats to get foul balls. Very scary."
Brewers spokesman Tyler Barnes said privacy laws prevented them from releasing any detailed information about the person or the incident.
"He was observed by fans after the fall moving all his extremities," Barnes said.
Brewers head athletic trainer Roger Caplinger said the man was cut and bleeding from the face, but was conscious as he was taken off the field by emergency first responders. He was taken to a local hospital, but there were no immediate details on additional injuries.
A hospital spokeswoman said she could not reveal any details about the injured man, citing privacy laws.
"Hopefully, he'll be fine," Theriot said.
Several Cubs players went over to see what had happened as well as Chicago's athletic trainers, and the incident held up batting practice for about 10 minutes.
Barnes said severe injuries have been extremely rare at Miller Park, which has been open for 10 years.
In 2004, a 48-year-old Madison man died a day after injuries he suffered when he fell 17 feet from an escalator. Three ironworkers were killed in the construction of the park in 1999 when a crane collapsed because of high winds.