Because of productivity or opportunity, some players just have another team’s number.
Marcus Allen, the Pro Football Hall of Fame running back, is still the record holder for most career rushing touchdowns against the San Diego Chargers. He was a great running back, but he also played his entire career with the Los Angeles/Oakland Raiders and the Kansas City Chiefs, meaning he was in the same division as the Chargers from 1982 to 1997.
Over the course of that time, Marcus Allen racked up 23 career rushing touchdowns against San Diego.
The second most rushing touchdowns against the Chargers is 8 and is held by four players: Pete Banaszak of the Raiders, Floyd Little of the Denver Broncos, and Curt Warner and Chris Warren of the Seattle Seahawks.