Officers believe he may hold important information about the incident, which happened outside of the One Stop shop in Warmsworth Road, Balby.
The incident happened at around 8.30pm on Wednesday November 9, but police only released details today.
A 29-year-old man left the shop, where he approached a man, asking to borrow a lighter.
It is then reported that the man assaulted him, before stealing his electronic tablet.
The victim was left with minor facial injuries as a result of the incident.
Following extensive enquiries and CCTV analysis, police are now asking for the public's help.
A South Yorkshire Police spokesman said: "Do you recognise the man pictured? Three other men were also around at the time of the incident, were you one of them?
"If you can help, please call 101 or email [email protected] quoting incident number 1119 of 9 November 2016.
Information can also be given anonymously to Crimestoppers on 0800 555111."