If you noticed the 49ers defense sagging a little bit near the end of 2012, there's a good reason: Justin Smith was injured. Smith is the lynchpin for that D and he'll keep playing that role for at least three more years, as the 49ers have locked up on an extension through 2015.
The #49ers have signed DT Justin Smith to a two-year contract extension through 2015.— San Francisco 49ers (@49ers) June 19, 2013
Smith's a fascinating case for a few reasons. One, he was a very nice player in Cincinnati, compiling 43.5 sacks as a defensive end for the Bengals in seven seasons. But he's absolutely flourished in San Francisco. He has compiled 32 sacks in five years (from age 29 to 33) and has become one of the more dangerous defenders in the league. His ability to, ahem, open up holes for guys like Aldon Smith can't be overstated -- Aldon's sacks disappeared following Justin's triceps injury in late December last year. (Even if Justin doesn't think that was the cause.)
Then there's the media coverage. For a while, Smith was the single most underrated player in the NFL. In the past two years or so, he's gotten his due, tilting a touch towards overrated and then finally settling in as properly rated. His 2011 season was his first as an All-Pro and third as a Pro Bowler (he picked up a fourth in 2012) and it was the full recognition he deserved. That's sometimes just life as a 3-4 end not named J.J. Watt.
Anyway, Smith's a big-time contributor to the 49ers defense. They need him healthy and on the roster, and with him headed into the final year of his deal, it makes sense to work out an extension.
The money will be fascinating, though, considering that Smith turns 34 in September of 2013. With the 49ers not too far under the cap when they made this deal, it's hard to imagine them throwing huge dollars his way to keep him locked down through the age of 36.
But a deal makes sense for both parties. It would mean Smith can retire with the Niners, it means the Niners keep a critical cog to their defense on board, and it means that the team can maneuver a little money around.