For the 49ers, run defense is an aspirational thing.

In 2013, the Bears allowed 100-yard rushers in six straight games: those players were Eddie Lacy, Reggie Bush, Ray Rice, Benny Cunningham, Adrian Peterson, and DeMarco Murray. Chicago was the 5th team since 1960 to allow such a streak.

In 2007, the Browns began the season by allowing 100-yard games to Willie Parker, Rudi Johnson, LaMont Jordan, Willis McGahee, Sammy Morris, and Ronnie Brown.

In 2006, the Rams had their own six-game stretch of allowing opposing running backs to hit the century mark: those backs were LaDainian Tomlinson, Larry Johnson, Maurice Morris, DeAngelo Williams, Frank Gore, and Edgerrin James.

In 1998, the Bengals allowed an opposing runner to hit the 100-yard mark in six straight games: Priest Holmes, Kordell Stewart, Eddie George, Napoleon Kaufman, Terrell Davis, and Fred Taylor were the stars there.

The first time, since at least 1960, that a team allowed a player to rush for at least 100 yards in six straight games came in 1979, against the Raiders.  Oakland only allowed six 100-yard rushers all season, but it happened in consecutive weeks  by Paul Hofer, Earl Campbell, the 7th best player named Mike Williams in NFL history, Rob Lytle, Chuck Muncie, and Mike Pruitt.

But now, for the first time in NFL history, the San Francisco 49ers have allowed a 100-yard rusher in seven straight games. Fozzy Whittaker went 16-100 in week 2, Christine Michael had 20-106 in week 3, Ezekiel Elliott had 23-138 the next week, David Johnson went off for 27-157 in week 5, LeSean McCoy ran roughshod 19-140-3 the following week, and Jacquizz Rodgers had 26-154 last week.

Today? Mark Ingram had 15 carries for 158 yards.  Up next week? A rematch against David Johnson and the Cards.