Coach Jeff Fisher said Monday that Saffold has a third-degree MCL sprain and other damage to the knee, but said it was not season-ending.
"He's going to miss a number of weeks. How many weeks, I can't speculate now," Fisher said. "He's got a pretty good attitude about it. He's happy with the news that we got as a result of the MRI."
Saffold was hurt advancing a fumble in the first quarter Sunday in the Rams' 31-28 victory over the Redskins. He was a surprise starter after being hospitalized with a neck strain in Detroit after the opener and listed as questionable prior to the game.
Fisher did his best to dispel rumors that running back Steven Jackson had been benched for spiking the ball in protest after he was ruled short of the goal line on a third-down carry from the 1, but was held out with a minor groin injury but could have returned in case rookie Daryl Richardson faltered.
"His groin was tight, we didn't want to risk further injury," Fisher said. "He could have come back in the game, and he was OK with it. He understands this is a long season
"When you're competing in a ballgame like that, you don't want to set yourself back. He's clearly not ruled out for this game."
Fisher repeated his assertion from Sunday that Jackson had been spiking the ball because the player thought he'd scored. Jackson's touchdown move is rolling the dice.
"I'm 100 percent sure the reason he spiked the ball was because you're allowed to spike the ball after you score a touchdown," Fisher said. "Listen, it didn't have anything to do with anything else but that."