MONTREAL -- Montreal police (SPVM) investigators are trying to determine how and why a man wound up in the middle of the road with a severe head injury early Saturday morning.

Police are reporting that officers responded to a 911 call around 5 a.m. after a 31-year-old man was spotted unconscious in the middle of 9th Ave. in Lasalle at Centrale St.

He was transported to the hospital.

"The man was conscious but not able to tell us what happened," said SPVM spokesperson Jean-Pierre Brabant.

Investigators are trying to determine what led to the man being injured in the middle of the street.

"Is it an altercation, an assault, an accident? For now, we're trying to understand," said Brabant. "We don't have any witnesses that could tell us what happened."

Brabant said it likely wasn't a hit-and-run as there was no other debris found at the scene and that the man had a single injury.

"Did he get a baseball bat to the head, did he get beat up, did he fall on the ground? We don't know," said Brabant.

An investigation is continuing.