King, 24, who spent much of his rookie season last year on the Vikings' practice squad, was in custody at the Anoka County jail Sunday and could be charged Monday, the Minneapolis Star Tribune reported. He was being held initially on suspicion of third-degree assault, the St. Paul Pioneer Press reported.
King allegedly assaulted Andrew Hayek, 22, of Coon Rapids at a 21st birthday party for a female friend in the Minneapolis suburb of Oak Grove early Saturday, the Anoka County Sheriff's Office said. The Pioneer Press said Hayek needed more than 50 stitches to close his wounds.
Hayek remained hospitalized Sunday with a fractured skull and facial injuries. His sister, Jenny Eagle, said he was "up and moving and doing better," the day after authorities had said he may have suffered a serious brain injury, the newspaper said. Eagle, a registered nurse, said hospital staff told her family it could be two weeks before physicians can determine whether there is long-term damage.
"My brother wouldn't start this," Eagle said. "He's in a lot of pain."
King is listed as 5-foot-11 and 217 pounds. Eagle said her brother is 5-foot-6 and 130 pounds.
Eagle, who was not at the party, said she was told that several hours into the party, her brother told King he resembled the comedic actor Eddie Murphy, triggering a dramatic mood change in the football player.
An Anoka County sheriff's report stated Hayek went outside to wait for a ride home, but King confronted him and punched him in the face. Hayek climbed into a car, locked the passenger door and called 911, but King allegedly got in through the driver's side door and pulled him from the vehicle. King struck Hayek several times in the head and then slammed him head-first to the ground, the report said.
The Pioneer Press said the arrest report states King denies assaulting Hayek, saying he "simply fell to the ground when King was talking to him."
Vikings General Manager Rick Spielman said he was aware of the arrest but had no further comment.
"We're still collecting and gathering information," he said.