One could argue (and one probably should) that the best free agent signing in the history of the San Francisco 49ers occurred in the 2008 off-season. That was when then head coach Mike Nolan took a former Cincinnati Bengals' defensive end on a helicopter tour of San Francisco in an effort to get him to sign with the franchise. Whatever was said on that ride in the sky and the hours surrounding it convinced the defensive lineman to cancel his planned visits to Minnesota and Jacksonville and sign with the 49ers. Six years later, Justin Smith has proved to be worth every penny of his 45 million dollar contract.

Affectionately nicknamed "Cowboy" by his teammates, Smith has been the lynch pin of a 49ers defensive that has been one of the best in the league in recent years. Smith is not the type of player whose stats tell the whole story. Instead, it's the little things he does like pushing the pocket or commanding double teams to free up other players. It's his non stop motor that makes him a nightmare to deal with for opposing offensive lineman. Smith said it himself on NFL Network after a Thursday night victory against the Seahawks, "Stats are for losers."

Smith has made the pro bowl each of the last four seasons and was so good in 2011 that he was the first player ever to be named All-Pro at two different positions. His importance to what the 49ers do defensively was never more evident than when he he was injured and not playing last season. According to Todd McShay, the 49ers defense recorded a sack once every 16.2 drop backs when Smith was on the field and once every 29.4 when he wasn't. Looking deeper, they allowed 2 touchdowns on 305 rushing attempts when Smith was in the game and 5 touchdowns on 102 rushes when he was not.

2013 marks the last year of Justin Smith's contract. Could this year be his swan song with the 49ers? Smith looks to be fully recovered from the triceps tear that caused him to miss time at the end of the regular season and be a shell of himself in the playoffs. But the Cowboy will be 34 years old this season and doesn't want to stick around if he can't be the type of player he has been in the past.

"I don't want to be the guy who becomes the third down guy who plays 17 (snaps)," said Smith. "I don't want to do that."

But it's not out of the question that Justin Smith may have more than one season of quality football left in him. What the team (and Smith) will have to weigh is how much those years are worth. The 49ers have a number of significant core players up for contract extensions in Colin Kapernick, Mike Iupati, Aldon Smith, and Michael Crabtree. If Justin Smith were to come back on a short term deal, it would most likely have to be at a reduced rate. One idea, if Smith remains healthy and effective, would be to take it one-year at a time with cap friendly deals that are incentive based.

Even though Smith remains an option past 2013, the 49ers have begun to plan for life without him. They spent a second round selection in the 2013 draft on defensive end Tank Carradine. Carradine projects to be Smith's eventual replacement when the time comes. Smith, however, remains focused on the present.

"You can't really forecast past the year you're in. I'm thinking about 2013 and 2013 only. We have our team back for the most part, added some other pieces. The goal is still the same as last year. Got close. Didn't get it done. Hopefully we get it done this year."

He's right. San Francisco's championship window is still wide open and the team needs Smith to be his dominant self to make another run at the Super Bowl. The 49ers are hoping their cowboy has at least one last good ride in him.