Two young attackers are said to have cornered their victim on a Scunthorpe Street before assaulting him and leaving him with a fractured cheekbone.
The 51-year-old victim was on Collum Avenue near St Bedes playing field at around 5.30pm on Wednesday, March 27 when the assault happened.
The two attackers approached him on the same pushbike.
A man jumped off the bike, confronted the victim and allegedly hit him.
The victim was knocked to the floor and later required hospital treatment.
Humberside Police said: “The men on the bike have both been described as white and in their early 20s.
“One was of skinny build, had a skinhead, and was wearing a grey t-shirt, black bottoms and grey trainers.
“The other who was wearing black clothing had black hair worn in a ponytail.”
Anyone who witnessed the assault or has information is being asked to call 101 quoting 16/41562/19.