Defensive Line
The 49ers plan to switch between a 4-3 and 3-4 base set this year. When they are in a 4-3, Anthony Adams will start at the nose while veteran Bryant Young will play the one gap. When they shift into the 3-4, big rookie Isaac Sopoaga may replace Adams at the nose. Sopoaga has the size and strength to take on multiple blockers, but his lack of experience is a concern.
At defensive end, Andre Carter is the best pass rusher on the line, but he needs to pick up the production this year. The 49ers will return both starters on the ends with John Engelberger taking the left side again. He is a hard-nosed player, but he lacks the size and strength to dominate at his position and will be little more than adequate. He could be challenged by Brandon Whiting, who was acquired from the Eagles in the Owens deal.
Linebackers
Julian Peterson is the biggest impact player on this defense, but at the time of this report, he and the 49ers were nowhere near working out the long-term deal he and his agents are looking for and he is sitting at home instead of working out with the team. And with the introduction of the 3-4 into the defense, it is important that he get as much time as possible working in the new system. Without Peterson, the 49ers are very thin at linebacker.
Derrick Smith, a solid run stuffer will return to the inside while Jeff Ulbrich will compete with Jamie Winborn, if he can stay healthy, for the right outside linebacker position. Both players will probably play when they are in the 3-4. After that, San Francisco has little more than special teams talent on the bench. If Peterson were to sit out for an extended period of time and Winborn has problems with injuries again this year, they might as well scrap the planned shift in defense.
Secondary
Ahmad Plummer and Mike Rumpf will start at the corners , but neither is what you would call a shut-down player. Shantae Spencer has the potential to be just that, but he is raw and will likely guard the slot in his first season. The loss of Jason Webster may hurt them in the short term, but Spencer has a much bigger upside and could challenge Rumph for a starting job as early as 05. Jimmy Williams will come into games in dime situations, but his lack of mobility could be a liability.
Tony Parrish, an intimidating hitter with good range, is firmly entrenched as the starter at strong safety. Ronnie Heard and Dwaine Carpenter will battle for the starting free safety position with the loser likely taking the No. 3 role. Either should be an improvement over last years starter Zack Bronson. Sixth-round draft pick Keith Lewis should provide some depth behind Parrish.
Overview
This is far from the 49ers franchise of the 80s and 90s. The offense is either inexperienced or lacks depth at nearly every position. An injury here or there could severely cripple this offense. Their defense will keep them in games provided they get Peterson into camp soon, but if their offense generates a bunch of three-and-outs, they wont be nearly effective as last year.
The team is going through a huge transition this year losing three veteran playmakers on offense, and despite the potential of some of the youngsters, it wont be easy to replace that production. I expect the 49ers to struggle, sometimes significantly, on offense, but they should be solid defensively. They no longer have the talent to compete with the Seahawks and Rams for the division title, and a playoff appearance is a long shot. Most likely they will spend the season trying to stave off the Arizona Cardinals.

