It happened around 10:30 p.m. at the Houston Sportsplex in the 12600 block of South Main St.
"This started over something as simple as a foul ball during a softball game," Houston police Lt. W.L. Meeler said. "From what we understand, there were as many as 300 people out there."
A man pulled out a weapon during the ordeal and shot another man after fearing for his life, according to detectives.
While it wasn't clear what exactly happened, the shooter was cooperating with investigators and no arrests had been made as of Friday morning.
Investigators were still working to find answers and review video from the area.
One weapon was located at the scene. The 32-year-old victim's identity was not released.