The victim, identified as 18-year-old Connor Golden from Fairfax, Virginia, was walking with two friends when he stepped on something and it blew up, according to witnesses.
Police said witnesses told them the man had just stepped onto a rock when an explosion occurred. People in the area said the explosion was heard blocks away.
"We were climbing down the rocks, Connor was 6 feet behind me and all of a sudden I felt the explosion on my back," said one of Golden's friends, Thomas Hinds. "The explosion sounded like a gunshot next to my ears. I turned around and saw his foot which wasn't completely blown off, but was severely mutilated. My other friend Matthew was behind Connor and all he saw was massive amounts of dirt go flying up in the air."
Golden suffered a severe leg injury, and the New York City Fire Department confirmed he was taken to a nearby hospital with a "possible amputation" to his right foot.
He was listed in serious, but stable condition.
At a press conference, officials stated they believed the explosion was caused by an "experiment" of fireworks or a homemade device. There was no evidence suggesting that the explosion was terror-related, authorities said.
The NYPD said there was a bag or a wrapping of what appeared to be from fireworks recovered nearby.
Police were still trying to determine who the device belonged to and said Golden and his friends were innocent victims. Officials said the device had been left in Central Park for approximately one day.
Hinds insisted that he, Golden and a third friend with them, Matthew Stabile, did not have fireworks.
"This was definitely not a firecracker. The police were understandably going at us hard asking about firecrackers because the idea that there would be some sort of bomb in Central Park is really scary," Hinds said.
Hinds said the group was planning to go Upstate New York to go camping.
The NYPD bomb squad was at the scene, and authorities closed off part of Central Park during its investigation.