The Oakland Raiders emerged as one of the premier teams in the NFL last season behind the play of their explosive offense.

In the process, what else became evident was their glaring issues defensively that often put their offense in a bind. However, this didn't lead to the front office actively looking to improve on that side of the ball over the offseason.

This has frustrated reigning NFL Defensive Player of the Year Khalil Mack, who recently stated to The Athletic that he was surprised by the lack of movement from the organization.

“That was a shocker for everybody,” Mack said. “Well … I know Bruce (Irvin) and I talked about it a lot. Yeah, that was unexpected. But those guys upstairs know what they’re doing. We trust in them. And not only that, but we’re all we’ve got and we’re all we need.

“That’s kind of how I look at it. We’re rolling with whoever is out there, and those 11 guys on the field are going to do whatever we can to be great.”

If the Raiders are hoping to take the next step, there will need to be some drastic changes made defensively. The bulk of the issues lie in the secondary that ranked 24th in passing yards allowed while giving up 27 touchdown passes.

There is also a need to add more pass rushers alongside Mack as Oakland finished the 2016 season with a league-worst 25.0 sacks, which the 26-year-old was responsible for 10.5. Things didn't fare much better against the run as they gave up 117.6 rushing yards per game last season, which was the 10th worst in the league.

It has become quite clear that the Raiders have plenty of issues defensively, and those problems will persist until the front office makes a concerted effort to truly address them.