TMZ Sports reported police in the Los Angeles area responded to a call Sunday, but Penn had already fled the scene when they arrived. The report says Penn was "at the house earlier and got handsy with his wife, at one point slapping her butt."
Penn then allegedly grabbed his wife's wrist and poured a drink over her head during a verbal dispute. No charges have been filed at this time.
Penn and his wife later issued a statement through their representative Denise White, denying there was a physical incident, via TMZ:
"There was a verbal disagreement, there was no physical altercation. The two are in the middle of a divorce and it is a hard time for both parties."
The NFL does not require formal charges or a conviction to make a player subject to its Personal Conduct Policy. Regardless of the outcome of the police investigation, the NFL will likely conduct one of its own to see if Penn violated any league rules. A standard suspension for domestic violence is six games.
Penn, 35, started 14 games for the Raiders last season. He is owed a $6 million base salary for 2018, half of which is guaranteed, per Spotrac.
In the event of a suspension, the Raiders could look to void that guaranteed portion of the deal, depending on the language in the contract.