Chicago Bears free agency targets: Chris Culliver

It's obvious that the Bears need to invest the most resources into the defensive side of the football because they've fielded the worst units in franchise history in consecutive seasons.

They have issues at every level of the defense, but the pass defense has been especially atrocious. Since cornerback Charles Tillman went down back in 2013, it seemed like the defense was never really able to recover.

Tim Jennings, who was playing the best football of his career alongside Tillman, suddenly didn't seem so great when he was manning the field by himself.

Last season the Bears ranked 30th in pass yards allowed and 31st in pass touchdowns allowed. This included allowing QBs like Ryan Tannehill (25/32 for 277 yards 2 TDs) and Matthew Stafford (34/45 for 390 yards 2 TDs) to look like top tier players. I'm not even going to remind fans of what Aaron Rodgers and Tom Brady's stat lines looked like.

While last season's first round pick Kyle Fuller looks like he has a bright future, the Bears could use some investment into resources at cornerback.

The Bears might not be able to spend a huge amount of money at CB, and Jennings is likely to be back thanks to his huge contract extension that would carry $6.65 million in dead cap money if he were released. His contract counts $5.25 million this season. But the Bears could use another CB because last season they wanted to bump Jennings inside to nickelback and, in the current pass-happy NFL, three solid CBs is a need.

Look no further than San Francisco 49ers CB Chris Culliver.

When I wrote my first free agent post on Monday, some of the commenters suggest I look at unrestricted free agents who have a connection with the Bears' new staff.

Culliver has played his entire career for new defensive coordinator Vic Fangio and defensive backs coach Ed Donatell. Culliver was a third round pick in 2011 out of South Carolina in Fangio and Donatell's first season with the 49ers.

Since then Culliver has been a role player, starting only 20 games, 14 of which came last season. Culliver has seven career interceptions, two forced fumbles and 111 tackles. He missed the 2013 season with a torn ACL.

Last season in his 14 starts he had four interceptions, 15 pass deflections and a forced fumble.

Culliver, 27, gets high grades ProFootballFocus as well. They have him graded as the third best free agent CB with an overall rating of 8.5. He also ranked 10th in PFF's signature stat Yards per Cover Snap, which rates a CB by how many yards a CB allows when they are in primary coverage on a per snap basis. He surrendered 0.95 YPCS on 491 coverage snaps. Opposing QBs had a 66.5 ratings on those snaps.

For comparison, Jennings surrendered 1.09 YPCS on 601 snaps, allowing QBs a 106.7 rating.

But can the Bears afford one of the best CBs on the market? Culliver might be cheaper than these grades suggest because he has some off-field issues.

Culliver was in hot water during Super Bowl week two years ago when he said that a homosexual player would not be welcome in an NFL locker room. He also had a minor problem dealing with social media, and last March was arrested following a hit-and-run crash and possessing brass knuckles.

These issues, combined with his lack of vast starting experience, means that perhaps the Bears could get Culliver on a team-friendly deal and get a solid player.

Is Culliver a player you'd be interested in the Bears pursuing?