Jon Gruden: Raiders got to be better on defense in '18

The Oakland Raiders' struggles on defense -- especially in the secondary -- were among the major roadblocks that stymied their 2017 playoff aspirations after a promising 2016 campaign.

Improving Oakland's dismal defensive performance is among coach Jon Gruden's top priorities for his first year back in Silver and Black -- regardless of whether contract holdout Khalil Mackis on the field or not.

"We weren't very good last year on defense withKhalil Mack," Gruden told NFL Network's Michael Robinson and David Carr on Inside Training Camp Live on Monday. "We've got to get a better pass rush, we've got to play better defense, period. And we hope Khalil gets here, but in the time being, we've got plenty of guys who need work."

There's no questioning Mack's role as the centerpiece of the Raiders' defense, and it's scary to think how poorly the Raiders would have performed without his 10.5 sacks and 78 tackles. Still, Gruden is right in basically saying everyone else around Mack has to improve their game.

The Raiders ranked 23rd in total defense (350.1 yards per game), and they didn't have an interception until Week 12 en route to tallying a league-low five picks for their 26th-ranked passing D.

With Oakland embracing a new-look secondary that includes Rashaan Melvin, Daryl Worley, Shareece Wright, Marcus Gilchrist and Leon Hall, Gruden and coordinator Paul Guenther will try to whip up concrete out of last year's Jell-O. If Gruden can orchestrate a turnaround there, it'll go a long way toward improving the defense overall and quieting the "back to 1998" naysayers.

Whether they can count on Mack -- and a healthyGareon Conley -- by the time the season starts remains to be seen.