Officers responding to a domestic disturbance call allegedly involving Dunlap and his girlfriend learned of the protective order upon arriving on the scene.
Dunlap, who reportedly knew about the order, was arrested and given a $1,000 bond.
"We are aware of the situation involving King Dunlap," the team said in a statement released Friday, according to Eric D. Williams of ESPN. "We will continue to gather information and monitor the situation as the legal process runs its course."
The 31-year-old has spent the last four seasons with the Chargers, starting in each of his 46 games over that stretch. He'd spent the five years prior with the Philadelphia Eagles after being selected in the seventh round of the 2008 draft.