The security guard was hit in the face during an attack involving three people. This happened about 6AM, the 7th of Feb.
A spokeswoman for West Midlands Police said:
"Police are investigating an assault at Asda in Old Horns Crescent, Great Barr, Birmingham which took place just before 6am this morning.
"It’s alleged that three people were involved in an altercation with a security guard who was hit in the face, causing a minor injury."