"Deputies have arrived on scene and are currently gathering more information. We do not believe this is an active shooter incident," Sheriff's Office spokeswoman Teri Barbera told the Palm Beach Post.
"Suspect information and motive of the altercation is unknown at this time," she told the newspaper.
Spectators and students fled the bleachers following the incident.
A helicopter later landed on the field where a man was being treated, according to the Palm Beach Post.
The victims have been taken to area hospitals, according to police. They were not students, police said.
FHP spokesman Lt. Alvaro A. Feola said in a statement early Saturday that both victims remain hospitalized, and one is in critical condition.
Read more on the Palm Beach Post here.