The 49ers run a base 3-4, but if the Falcons stick with 3 WR sets, I expect you'll see more of the 49ers nickel than their 3-4. In the nickel, Sopoaga comes off the field, Smith and McDonald move into the two defensive tackle positions, and OLBs Ahmad Brooks and Aldon Smith take over the defensive end roles.
Justin Smith is the key to this group. He missed the team's final two and a half regular season games with what was described as a partially torn triceps muscle, and his absence was noticeable. He clears the way for OLB Aldon Smith, and generally commands double teams on a lot of plays. There are questions about if he is close to 100% or not, but the Packers treated him as such, double-teaming and doing what they could to keep him away. Sopoaga is solid at collapsing the pocket for the linebackers, and is very solid against the run. Ray McDonald does the dirty work opposite Justin Smith, and has proven to be a very solid defensive end. Ricky Jean-Francois is the utility lineman, able to fill in at both nose tackle and defensive end.
LinebackersStarters: OLB Aldon Smith (99), ILB Patrick Willis (52), ILB NaVorro Bowman (53), OLB Ahmad Brooks (55)Reserves: Larry Grant (54), Tavares Gooden (56), Michael Wilhoite (57), Clark Haggans (51), Cam Johnson (50)
The 49ers OLB corps is the best in the league. I normally would include the word "arguably", but when you have three linebackers selected first team All-Pro, and the fourth selected second team All-Pro, I don't know how much else needs to be proven. Smith and Brooks bring most of the pass rush heat, but the team does a good job of frequently sending Patrick Willis up the middle on blitzes. Willis and Bowman are both in on the team's nickel D, and then they generally rotate in the dime. Willis is the primary defender against tight ends, and likely will get plenty of work against Tony Gonzalez. If either ILB gets hurt, Larry Grant is the first off the bench. If either OLB gets hurt, Clark Haggans is the first off the bench.
SecondaryStarters: CB Carlos Rogers (22), CB Tarell Brown (25), FS Dashon Goldson (38), SS Donte Whitner (31)Reserves: CB Chris Culliver (29), CB Perrish Cox (20, CB Tramaine Brock (26), S C.J. Spillman (27), S Darcel McBath(28), S Trenton Robinson (30)
The 49ers secondary can be a bit up and down at times, in part because of the softer D we sometimes see between the 20s. The team does a good job of clamping down in the red zone, but they can give up a decent amount of yards at times. They are an aggressive group, that can play with plenty of physicality. Chris Culliver is listed as a reserve, but if the 49ers go with a lot of nickel, as expected, he will get a lot of playing time. In the nickel, the 49ers move Carlos Rogers into the slot, and then insert Culliver on the outside. Rogers can be beaten in the slot, so his matchup will be the one to watch all game long. C.J. Spillman is the first safety of the bench, while Perrish Cox is the first corner off the bench. Tramaine Brock will get his share of time as well.