On Justin Smith's new contract extension

The San Francisco 49ers have announced a contract extension for one of their best players.

Defensive lineman Justin Smith, who turns 34 on Sept. 30 and is coming off triceps surgery, is now signed through the 2015 season. His contract was previously set to expire following the 2013 season.

2011-12 DL Snaps Counting Playoffs

It's not yet clear whether this contract extension means much in relation to how long Smith will factor along the defensive line. His health is the key variable there. But if Smith remains healthy and productive, there's no chance he'll leave the 49ers as an unrestricted free agent after the upcoming season. That's good for the team.

"Justin's All-Pro contributions on the field, as well as his leadership on and off the field, are integral to our success as a team," 49ers general manager Trent Baalke said in a statement released by the team. "Justin consistently sets a standard of excellence, serving as an example for everyone within our organization. This contract allows Justin to finish his career as a 49er!"

Financial details are not yet known.

Did the 49ers add years primarily to reduce the scheduled $8 million charge against the 2013 salary cap? They easily could have converted Smith's scheduled $7.5 million salary for 2013 into a signing bonus, then added years to spread out the cap charge. The statement from Baalke suggests this was more than just a procedural move.

Smith has been one of the most durable players in the NFL, starting 185 consecutive regular-season games until suffering the triceps injury late last season.

As the chart shows, Smith and 49ers teammate Ray McDonald rank among the league leaders in snaps played for defensive linemen over the past two seasons, counting playoffs. Those postseason snaps have come into play for Smith only over the past two seasons, putting additional strain on his body.

Smith has said in the past he doesn't want to become just a rotational player in his final seasons. Reducing his snaps to some degree would make sense, however.