Police are trying to identify this man who collapsed while jogging in Prospect Park Dec. 31, 2013. View Full Caption NYPD

PARK SLOPE — A man who collapsed while running in Prospect Park on New Year's Eve has been unconscious in a hospital bed for more than a week as detectives try to identify him, police sources said.

The man, who is believed to be approximately 60 years old and has thinning gray hair, was spotted running in Prospect Park on Dec. 31, police said. He collapsed about 1 p.m. and was rushed to New York Methodist Hospital, where he was in critical condition, according to police.

The man had no identification on him and was carrying only an asthma inhaler, the source said.

He stands 5-foot-9 and weighs 200 pounds and has brown eyes, police said. He was wearing blue jogging pants and jacket, and black, size 9 1/2 Adidas sneakers when he fell.

The case has been referred to the NYPD's missing persons unit, the source said. A spokeswoman for New York Methodist referred questions to the NYPD.

At least three local runners have visited the nameless jogger to see if they recognized him, said Michael Ring, vice president of the Prospect Park Track Club.

Ring went to the man's bedside in the intensive care unit on Sunday after hearing about the case from other runners. The man — who Ring described as "middle-aged, slightly overweight and balding" — didn't look familiar.

Ring took a moment to speak to the man, who was unconscious and had a tube in his mouth. "I kind of awkwardly said to him, 'Sir I don't know you, but I hope you’re going to be OK.'"