How effective will Justin Smith be on Saturday?
That is the key question facing the 49ers as they prepare for the Packers. If Smith is healthy, the 49ers will have a formidable pass rush and can harass Aaron Rodgers and degrade his passing game. A healthy Justin Smith makes Aldon Smith a better sacker of quarterbacks. If Smith is healthy, the Niners can almost certainly negate the Packers' run game.
But if Smith is not healthy — if he is not Justin Smith — the 49ers' defense is no big deal. Think back to the second half of the Patriots game on Dec. 16 and the Seahawks game on Dec. 23 when Smith could not play because he injured his left triceps.
The 49ers really need Justin Smith to be Justin Smith.
I phoned Santa Rosa resident Gary Furness, a doctor for the California Athletic Commission. Furness specializes in athletic injuries. Before discussing Smith, he wanted me to understand what the triceps does.
"The triceps muscle straightens out the elbow," he said. "Triceps injuries are rare except in weight lifters and football players. A lot of people have no idea what the triceps does. For Smith to be effective he has to be able push off."
Are you following? Smith pushes and pulls at the line of scrimmage. The triceps helps him do that. With a faulty triceps he's not much of a pusher.
Furness discussed two outcomes for Smith depending on the nature of his injury. Remember, the nature of his injury is murky. The Niners never have issued a news release detailing what happened, so there is an area of uncertainty.
The optimistic alternative, a muscle tear:
"Smith would be lucky if he tore a muscle instead of a tendon," Furness said. "If it's a muscle tear it can heal in three to four weeks and it almost never needs operative repair. It's also consistent the 49ers would try to bring him back in a month."