You are probably familiar with the name "Football Outsiders." The site often provides NFL content for ESPN. Vincent Verhei of Football Outsiders recently took a look at the NFC West teams, and each's biggest weakness that needs to be addressed this offseason.

Many fans and analysts would agree that an impactful pass rusher is the San Francisco 49ers' biggest need. Verhei went in a different direction, saying that the secondary is the most important area to fill. He notes that the 49ers defense ranked last on throws to the side of the field opposite cornerback Richard Sherman, who was by far the secondary's best player last season.

The defensive unit also ranked No. 19 or worse against No. 1 wide receivers, No. 2 receivers, all other wideouts, tight ends, and running backs, according to Football Outsiders' analytics. It also ranked No. 27 against short passes and No. 30 against deep passes.

Verhei notes that safety Jaquiski Tartt performed well despite playing just eight games in 2018 and eventually landing on injured reserve with a shoulder injury while Adrian Colbert struggled before suffering a season-ending high-ankle injury in October.

"Jimmie Ward, Antone Exum, and Greg Mabin are free agents, and John Lynch should just thank them for their time and let them walk," writes Verhei.

How should the 49ers address the secondary issues? The Football Outsiders feature suggests the team sign safeties Earl Thomas and Landon Collins, as well as cornerback Morris Claiborne. Then Verhei suggests the 49ers trade for Arizona Cardinals cornerback Patrick Peterson.

Thomas will be a highly-sought free agent. Peterson requested a trade in October but retracted the request days later. He told ESPN in January that he'll honor his contract, which runs through 2020.

Football Outsiders doesn't completely ignore the 49ers' need for a pass rusher and suggests the team address the position with the No. 2 overall pick in the draft.