Last offseason, the Oakland Raiders locked up the face of their franchise. This year, they may be on the verge of taking care of the centerpiece of their defense.

According to Vic Tafur, Oakland has made an offer to Khalil Mack, who is entering the final year of his rookie contract. Per Tafur, the linebacker is in the process of evaluating the offer.

Mack, the fifth overall pick in the 2014 draft, has been everything the Raiders expected and more. He has anchored the team's defense, averaging 76 tackles and 10 sacks in his first four seasons in the league. In 2017, he recorded a career-high 78 tackles and had his third consecutive season of double-digit sacks, finishing the year with 10.5.

Picking up the fifth-year option—which will pay him $13.8 million—for the 2016 NFL Defensive Player of the Year was a no-brainer. After the franchise went 13 years without making the postseason, the linebacker played a big part in ending the playoff drought in 2016. If not for Derek Carr's season-ending injury, perhaps the team could have made some noise.

No figures have been reported, but given the caliber of player involved, it won't be cheap for the Raiders to keep the three-time Pro Bowler around for years to come. Both Von Miller and Justin Houston have signed $100 million-plus deals with at least $50 million guaranteed in recent years. With Mack just turning 27 years old this month, he would likely be in line for a similar deal. 

If Oakland can sign Mack for the long haul, the organization will have cornerstones on both sides of the football to continue to build around. Carr and Mack have already shown they can elevate the team to contender status. If they can stay healthy, perhaps they can lead their franchise to a fourth Super Bowl championship.