The victim, a man in his 40s, was found injured by a member of the public in Quaker Way shortly before 6am on Saturday 25 February.
He was later treated in the hospital for a cut to his head and released.
DC Amelia Hicklin, of Nottinghamshire Police, said: “This was a nasty assault that took place somewhere in the in town centre in the early hours of Saturday morning.
“It is likely that this assault was seen or heard by somebody and I urge any witnesses to come forward.”
Anyone with information is asked to call 101 quoting incident 137 of 25 February 2023.
More news from Mansfield