A 25-year-old Toronto woman suffered minor injuries when Lynch's 2008 Porsche Cayenne is alleged to have struck her in downtown Buffalo before the vehicle fled the scene.
Lynch has not admitted that he was the driver of the vehicle, which was impounded after being found by police.
Clark refused to discuss the details of the agreement or Lynch's charges.
"This whole agreement is predicated on the fact that he was driving the car," Clark said. "Has he said that? The answer officially is no. The reason we are here and in these negotiations is all predicated on the fact that he was driving the vehicle. Ninety percent of matters like this are resolved by plea."
Lynch was Buffalo's first-round pick in the 2007 NFL draft out of California and rushed for 1,115 yards with seven touchdowns in his rookie season.