OAK GROVE — Minnesota Vikings running back Caleb King was arrested on suspicion of third-degree assault in the beating of another man outside a birthday party, the Anoka County Sheriff’s Office said Saturday.

King, who signed with the Vikings as a rookie free agent last year but didn’t play in a game, was jailed but hasn’t been charged.

The victim was a 22-year-old from Coon Rapids. King is accused of punching him repeatedly and throwing him headfirst to the ground. The man was hospitalized in serious condition with skull and facial fractures, as well as with cuts that required more than 50 stitches to close, Sheriff’s Cmdr. Paul Sommer said.

The man “may have a very serious brain injury,” Sommer said.

“I just was made aware of it today and I don’t have any further comment on it right now,” Vikings GM Rick Spielman said.

“We’re still collecting and gathering information, but we are aware of the situation.”