In today's salary cap era, it's extremely difficult, if not impossible, to keep a unit together. Eventually, you have to start making hard decisions on free agents. Eventually your players get old. Eventually you start having to pay players on the other side of the ball. Eventually you have to move on. Considering all of the obstacles, it's kind of amazing the 49ers were able to keep all of their defensive starters from 2011 (plus Aldon Smith and Chris Culliver) intact in 2012. But while the defense looked great on the surface, cracks had begun to form in its foundation. For the most part, the 49ers ignored those cracks, concentrating on offense last offseason. I'm not saying those moves didn't make sense but while the focus started to shift to the other side of the ball, the cracks in the defense got bigger and in some cases leaked. The reality is those leaks may have cost the team a championship.

Everyone saw what happened to the 49ers defense when Justin Smith and Aldon Smith were either injured or playing hurt. They could not get any pressure and as a result could not stop the pass. They were able to do enough to get by as the offense started to click but it eventually caught up to them. A lot of the blame shifted to the play of the secondary, but in reality, even the best corners and safeties can't cover when the quarterback has time to sit in the pocket and go through his progressions. The issue in the foundation was and is depth and unless the 49ers address that soon those cracks will start gushing. In some cases they have to be dealt with this year. In other cases, they have been patched up but will still need to be fixed long term.

Right now the most visible crack in the foundation is at free safety. Dashon Goldson was probably the best player on what was already a suspect secondary and he'll be playing in Tampa Bay this year. But the team had to let him go. They could not give their free safety a huge contract with Iupati, Davis (since resigned), Kapernick, Crabtree and Smith all up for extensions. I don't believe for a second that the signing of Craig Dahl is the answer nor do I think the 49ers believe that. This upcoming draft is deep at the safety position and with the 31st and 34th picks the 49ers could easily grab one of the top guys on the board (Vaccaro, Cyprien, and Elam are a some names linked to the team). With that in mind, it makes the loss of Goldson a little easier to take. But the cracks at safety don't necessarily end there. Donte Whitner is a free agent after this season and unless he comes back on the cheap he likely won't be back in 2014. Whitner struggles in coverage at times but he's terrific against the run and is a team leader. If Whitner hits the open market he'll likely get a contract offer that will be higher than the number the 49ers value him at. You could see another Craig Dahl type stop gap signing next season while they look to draft Whitner's replacement in 2014.

The crack that could spread the most is at cornerback. On paper, the team looks like they have more corners than they know what to do with. With Carlos Rogers, Tarell Brown, Chris Culliver, and Nnamdi Asomugha all completing for the top 4 spots, who needs to worry? Well, Roger's play has declined and he's not getting any younger. If his play continues to fall off he could see less snaps this year. Rogers is also not getting any cheaper and he's a likely candidate to get released after the season which would leave the team down one cornerback in 2014. Brown is in the last year of his contract. He's a good player and in the open market could get some big offers that I doubt the 49ers would match. His situation could be comparable to Whitner's where their market just exceeds what the 49ers are willing to pay. That leaves the team down two cornerbacks in 2014. Asomugha's not much more than a Randy Moss 1 year flyer signing. Barring a complete career resurgence, he's probably one and done in San Francisco. Even if he has that resurgence, the 49ers are not going to pony up big money for a player his age. That leaves them down three cornerbacks for 2014. Brock and Cox are on the roster but neither is more than a dime corner. Theres a good chance the team could only have Culliver under contract in 2014. So while cornerback is not a NEED for 2013 and they could certainly worry about it after this season, it's a position that could get ugly quickly if there is not a plan in place to reinforce its foundation.

The linebackers look to be the sturdiest part of the foundation but it can't be ignored entirely. No one worries about Patrick Willis or Navorro Bowman. They are durable and having two All-Pro inside linebackers isn't something most teams have. They're almost like depth for each other. That's not to say it's not important to have a Larry Grant type to back them up. Ahmad Brooks is steady and balanced but is not a big time pass rusher. Aldon Smith will be healthy again this year but he will need some help both in getting to the quarterback and getting some rest. The latter is why the return of Parys Haralson can't be overlooked. Haralson is tremendous against the run. He can spell Smith in early downs here and there to keep him fresh at the end of games and at the end of the season. But Haralson does not generate a lot of pressure which is why the 49ers substituted Aldon Smith on passing downs in 2011. Consider there were rumblings that the 49ers were looking to take Bruce Irvin in last year's draft if he was still on the board makes you think they may have at least briefly thought about doing something similar with Brooks and another pass rush specialist. No one knows what to expect from Darius Fleming or Cam Johnson coming off of injuries. Neither has played a snap in the NFL to begin with. It's possible the 49ers still look to add a situational pass rusher (either via the draft or free agent) at some point.

The Defensive line is the part of the foundation that is a ticking time bomb. Again, on the surface they look like a dominant unit. Justin Smith is a force of nature when healthy. Ray McDonald may be one of the most underrated players at his position in the NFL. Glenn Dorsey could be a steal at nose tackle. But Smith and McDonald have played a lot of snaps the past two seasons and logic would dictate wear and tear is going to come into play. The 49ers simply don't have players on the defensive line that can rotate in and make any kind of an impact right now. Ian Williams has never seen significant snaps and if an injury happens to any of their top three lineman (especially Smith or McDonald) the results could be worse than last year if the cracks have not been repaired. The draft is deep with defensive linemen and there will be good players on the board when (if) the 49ers make those first two picks (think Donte Jones or Margus Hunt). They could also package some of their picks to move up and get an impact defensive lineman like Sharrif Floyd. But keep in mind it doesn't have to be a first or second round pick to be a good pick and they could always address defensive line in the mid rounds as well. There's no harm in making multiple picks to help sure up this area. No matter how it's addressed, this crack has to be dealt with now. You can't expect Smith and McDonald to play the amount of snaps they have for a third year in a row.

Look, I'm sure I'm not saying anything here that Trent Baalke and Jim Harbaugh do not already know. Every good team is going to have cracks somewhere in their roster. These cracks can't always be fixed in one offseason. Sometimes you have to just patch them up (i.e. Asomugha, Dahl, Dorsey) while you wait to get the right pieces to reinforce them for years to come. Good organizations have a multi-year plan on how to fix those cracks and you'd better believe the 49ers are a good organization.

Al Sacco
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