Police in riot vans had to be called to a wedding party at Edgbaston Cricket Ground after a large brawl broke out.
A 38-year-old man suffered a leg injury and was taken to hospital amid the fighting, at 21:30 BST on Saturday.
West Midlands Police said officers were called to a "report of a disorder between a large group of attendees at a wedding party".
A 44-year-old man arrested on suspicion of assault has been released pending further investigations.
Witnesses reported seeing a dozen police cars and riot vans outside the famous stadium in Birmingham.
One onlooker, Kayleigh Elizabeth, posted on Twitter: "Major police incident - Edgbaston Cricket Ground , opposite Aldi.
"Looks like a car had been stopped. A dozen police cars and riot vans have flooded the area. Avoid if possible."
West Midlands Police said inquiries were ongoing.