Reuben Foster Is a Significant Upgrade for the 49ers' Defense

There was no time for training wheels in John Lynch's first draft as the general manager of the San Francisco 49ers, and they got the drama started early by making the first trade of the draft to move back just one slot.

San Francisco used that third overall pick to begin improving their defense, by adding defensive end Solomon Thomas. And then when it seemed like they were done for the night, the 49ers made another move to get back into the first round.

And that is where they selected Alabama Crimson Tide linebacker Reuben Foster.

Who Is Reuben Foster?

As a senior last year for the Crimson Tide, Foster led his team with 115 tackles, while also adding on 5 sacks. That was his second season as a starter, and his stellar play resulted in him winning the Butkus Award as the best linebacker in the country.

He was a menace against the run, leading all FBS linebackers in run-stop percentage and earning the highest run defense grade from Pro Football Focus.

He certainly won't be labeled one-dimensional, as his run-stop percentage topped all FBS linebackers last season, while he also had the eighth-best pass coverage grade among all linebackers to play at least 300 snaps in coverage.

Check him out showing off his speed, awareness, and pass defense to break up a pass across the middle.

At the end of the college football season, he was among the most heralded players in this draft. And then came the NFL Combine, which Foster was sent home early from after an altercation with a hospital worker. To make things worse, his drug test from that weekend came back positive for a diluted sample.

Those incidents resulted in San Francisco filling a need with one of the draft's most talented defensive players.

Strengthening a Weakness

One of our signature metrics here at numberFire is Net Expected Points (NEP), which measures the value added or lost on each play relative to league-average expectation. A defense giving up a 10-yard run on 3rd-and-8 should mean more to team's statistics than giving up a 10-yard run on 3rd-and-20, and NEP accounts for that.

San Francisco's 0.14 Adjusted Defensive NEP per play ranked 28th in the NFL last season. As bad as that sounds, they actually ranked worse in other categories.

They were the only team over the past three seasons to allow at least 30 points per game, and inside linebacker is certainly an area where they needed to improve.

Projecting Foster

Interestingly enough, one of the players Foster has been compared to is Patrick Willis, who led the 49ers defense for eight years before retiring at the end of the 2014 season.

Willis made an impact right away by leading the NFL in tackles twice over his first three seasons. This comparison is high praise for any player entering the league, but Foster has shown the ability to also be an impact player right away.

The question is more where he will line up on defense rather than figuring out if he's good enough to contribute right away. San Francisco has played primarily in a 3-4 defense for the past 10 years, but new defensive coordinator Robert Saleh has used a 4-3 base defense in the past. Foster will remain inside in a 3-4, likely bumping Smith to the bench, but also has the ability to play on the weak side if they line up in a 4-3.

However they line up, San Francisco has already upgraded their defense in a big way, adding two likely starters through the first round of the NFL draft.