The man, in his 40s, suffered a minor facial injury following the attack at the New Junction pub, between Rough Hay and The Lunt, Darlaston, on Tuesday night.
West Midlands Police was called to the pub, on Forge Road, at around 8.40pm and found the man intoxicated.
He declined medical treatment at the scene.
A West Midlands Police spokesman said: "Police were called at 8.40pm yesterday following reports of a man being assaulted in Forge Road, Darlaston.
"A man in his 40s suffered a minor facial injury."
Anyone with information can contact police via Live Chat at www.west-midlands.pnn.police.uk between 8am and midnight or call 101 anytime. Quote log number 2388 of 15/10/19.
Bilston Police tweeted: "Bilston NHT responded to a pub disorder last night, on arrival, intoxicated male with minor facial injuries was outside offender already left. He declined medical care and left scene."
The pub was approached for comment.