The 49ers are preparing for Sunday's game against Seattle with the assumption that defensive end Justin Smith won't be available. Smith left last week's 41-34 victory over New England in the third quarter because of an undisclosed elbow injury and did not practice on Wednesday or Thursday.
Smith's departure from the game nearly coincided exactly with New England's 28-point run that erased a 31-3 San Francisco lead.
"We got guys that can step up," safety Dashon Goldson said. "Justin is one of our captains, one of our leaders, one of our bell cows, but we definitely have some guys that will definitely have to step up and carry that load for us."
The likely candidate to step into Smith's role is Ricky Jean Francois, who had two tackles and a sack last Sunday.
"He's got good strength. He's a good athlete for a big guy," defensive coordinator Vic Fangio said of Francois. "He can play both the banging game and got a little bit of athleticism too, so he's a well-rounded player. He's the one guy on our front that can play all three spots and nothing will change with him in there."
Linebacker Aldon Smith, who needs three sacks during the final two games to tie Michael Strahan's NFL single-season record (22.5), has benefitted from playing beside Justin Smith all season.
"I don't know exactly how much (he's helped Aldon), but I know it's quite a bit and you judge that by the evidence that is there by the play of Aldon," coach Jim Harbaugh said. "Then, also the evidence of how much Aldon gives credit to Justin. But I think just even more so, you can see the respect that Aldon has for Justin and the way he listens to Justin, the way he just learns from him."
Justin Smith was a first-team All-Pro defensive tackle selection last year and a second-team pick at defensive end. He has 66 tackles and three sacks this season.