Shoring Up Defensive Line Is Key to 49ers' Long-Term Success

The San Francisco 49ers have many needs to address this offseason, one of the most pressing of which is on the defensive line.

San Francisco has long been strong on the D-line but heads into 2015 lacking some depth on that side of the trenches, even with the acquisition of Darnell Dockett on a two-year-deal, per the team's official website. Still, with free agency heating up and the draft drawing closer, it is the wide receiver position that is seen as the Niners' greatest area of need.

It is therefore somewhat surprising to see a host of mock drafts predicting the 49ers to again pass on a receiver in the first round and instead opt to bolster a defensive line that still boasts plenty of talent.

Indeed, NFL.com's Charles Davis has the Niners taking nose tackle Danny Shelton, while Lance Zierlein, CBS Sports' Dane Brugler and Todd McShay of ESPN (h/t David Fucillo of Niners Nation) all have San Francisco electing to select defensive tackle Arik Armstead from the Oregon Ducks.

With the paucity of playmakers the Niners have at receiver, it appears to be something of a stretch to suggest San Francisco will go in any other direction in the first round of the draft.

But, whether it be through free agency or the draft, this is a team that has always prioritized building from the trenches. And here I look at why doing so again this offseason will be key to the 49ers' hopes of maintaining the success they had enjoyed up until last season.

Assessing the Depth

Despite a raft of injuries, the 49ers defense still performed well in 2014 thanks in part to the form of the D-line. However, the issue San Francisco has is that at least one of the two veterans responsible for the strong play up front will not be with the team in 2015.

The team released Ray McDonald in December following more off-the-field issues, and it is still not clear whether Justin Smith will return for a 15th season in the NFL, although The Sacramento Bee's Matt Barrows has indicated that a decision may be around the corner.

Stephen Brashear/Associated Press/Associated Press

Smith and McDonald were ranked at No. 11 and 12 among all 3-4 defensive ends in the league, according to Pro Football Focus. Dockett will go some way to filling the void left by McDonald, but it figures to be tough for San Francisco to replace Smith should he decide to call it a career.

Cornellius Carradine and Quinton Dial—pressed into service at nose tackle because of injuries in the latter part of the season—both showed flashes toward the end of the year and, if Smith were to retire, are candidates to take the starting defensive end roles on the Niners' three-man defensive front.

Neither Carradine nor Dial can be considered proven, though, and the retirement of Smith would leave Tony Jerod-Eddie and Kaleb Ramsey—who redshirted his rookie year—as the only options beyond that of Dockett at defensive end.

The situation is not much better at nose tackle. Ian Williams' career has been severely hampered by injuries—he played just 10 games last year after missing almost all of the 2013 season—while Glenn Dorsey did not play a game in 2015 after suffering a torn bicep and will turn 30 before the start of the season.

In examining the Niners' depth on the defensive line, Smith, assuming he does return, is the only player they can have complete confidence in. But the 49ers have a number of ways in which they change that.

Free-Agent Options

The best way for the 49ers to shore up the D-line for the immediate future is to ensure Smith is back with the team. However, at 35, Smith's reps will need to be managed should he return, and the Niners have gone some way to ensuring that happens by signing Dockett.

Dockett missed all of last season with a torn ACL after previously sitting out just two games in his career. He will provide added experience and toughness up front and comes with a history of consistent production, having put 40.5 sacks prior to his injury. Yet the 33-year-old will likely only be a short-term contributor, and there is no guarantee of him performing at the same level coming off his knee problem. 

What the Niners need is new blood that can be a factor for many years to come. San Francisco hopes Carradine and Dial can be long-term contributors, but it would be wise to bring in another player with plenty of tread left on the tires.

Corey Peters of the Atlanta Falcons is a good fit as a run-stuffer and has the versatility to switch from a 4-3 to a 3-4, although there are concerns over his durability given that he has not completed a full season since his rookie year in 2010. At nose tackle, meanwhile, another Arizona Cardinal, Dan Williams, could be a nice, affordable option to compete with Williams and allow Dorsey to kick outside and start at defensive end.

Still, in terms of finding a replacement for Smith, the Niners would be better served looking to a draft class that is well-stocked with defensive line prospects.

The Draft

In terms of 3-4 defensive ends, Armstead is probably the 49ers' best option behind Leonard Williams, who is arguably the best player in the draft and will almost certainly be selected in the top five.

Armstead, at 6'7" and 292 pounds, is an explosive player who displays impressive athleticism for a man of his size. He has a good punch and uses his hands effectively, making him difficult to block one-on-one.

Indeed, Armstead consistently drew double-teams in the 2014 season and projects well as a defensive end in the Niners' 3-4 system with his ability to soak up blocks. His outstanding physical traits have not resulted in consistent production—he put up only four sacks in three seasons with the Ducks—but, although he could stand to gain another pass-rushing move to boost his numbers, Armstead is a player with the raw tools to be effective in the pros.

Texas defensive tackle Malcom Brown is another option in the first round who has the versatility to operate in a 4-3 or a 3-4 and is perhaps a better bet than Armstead to make an immediate impact as a penetrative force in the backfield following a 2014 season in which he recorded 6.5 sacks.

The Florida State pairing of Eddie Goldman and Mario Edwards both have the scheme versatility to play as 3-4 ends, and they are projected to be late first or early second-round picks. But the 49ers do not necessarily need to strike early to pick up a defensive end in a draft where there is value to be had in the mid-rounds at the position.

Stanford's Henry Anderson, regarded as a fourth-round pick by CBS Sports, would be an astute mid-round pickup after a final year with the Cardinal in which he racked up 8.5 sacks and 12.5 tackles for a loss—although, as Zierlein points out, there are concerns over his power that would need to be addressed in order for him to be a success as a 3-4 end in the NFL.

Corey Crawford of Clemson, who should also be available in the middle rounds, could be an interesting developmental prospect. But after sitting out the 2014 season opener for a violation of team rules, there are some questions over his character, something that cannot be said of top nose tackle prospect Danny Shelton.

If Shelton is still available when the Niners pick at 15, then it may be hard for them to resist a player who possesses the ideal size to serve as a two-gap defender at 6'2" and 339 pounds and has demonstrated the capability to shed blockers quickly to make plays against the run and pass, posting 16.5 tackles for loss and nine sacks in 2014.

Acquiring Shelton would reveal how the 49ers feel about Williams but also allow them to move Dorsey outside. Picking Shelton would have both short- and long-term benefits, which is exactly what San Francisco should be looking for when bolstering the defensive line this offseason.

Why D-Line Depth Is Key

There are plenty of avenues the 49ers can explore in terms of adding depth to the D-line, and considering the pieces they have up front already, it is vital that they do so even in a year when San Francisco has a number of other holes to fill.

Beyond Dockett, Dorsey and Smith, there is little in terms of experience on the defensive line. And if the latter retires, that will put a lot of pressure on players like Carradine and Dial, who only have one year of significant playing time under their belts, to perform the duties Smith and McDonald have fulfilled to an extremely high standard in recent times.

Both Smith and McDonald have excelled in stopping the run and soaking up double-teams to help pass-rushers such as Aldon Smith generate pressure while also harassing the opposing quarterback themselves.

The play of that duo has been pivotal to the Niners' success in the past few years and may be tough for Dial, Carradine or even Dockett to replicate. Dial had a decent year against the run in 2014; however, Carradine did not come on until late in the year and only really excelled as a pass-rusher, recording three sacks.

Dockett's main strength is also in rushing the quarterback. However, he has historically struggled in defending the ground game, earning a negative mark against the run from PFF in every year since it began grading.

Bringing Smith back to play alongside Dockett and Dorsey—assuming he wins the nose tackle job—would go a long way to solidifying things and give Carradine, Dial and Williams mentors to learn under. Yet, Smith is unlikely to be around for more than another year. Further reinforcements are required to help give the Niners a rotation to maximize the effectiveness of their elder statesmen up front and ensure San Francisco has the players capable of keeping the 49ers among the elite defenses in the NFL. 

Nicholas McGee is a San Francisco 49ers Featured Columnist based in Leeds, England. Follow him on Twitter @nicholasmcgee24.