Raiders head coach Jack Del Rio sees that as a distinct possibility.
"[Mack] plays defensive end already for us in sub packages. So I think it would be natural for him to be able to play whatever we decide is best for him," Del Rio said Tuesday at the league owners meetings. "However it helps the team best, he's gonna play. Last year the number of sub snaps in the league has gone up dramatically each year. I think we're up to close to 70% now of your snaps you're facing three and four receiver sets and so your sub packages where Khalil is and end is the one that really is the most prominent. So, he definitely has shown he's got the ability to be an edge rusher, a defensive end he is that in that capacity. I feel like it's however we want to be utilize him and who we have around him as well."
Part of the reason for this potential switch is Mack's tremendous pass rush abilities. The other part, as Del Rio points out, is personnel.
The Raiders didn't add a defensive end in free agency. What they did add was a couple of linebackers. The first day of free agency they added former Seahawks outside linebacker, Malcolm Smith.
Smith can play at either strong side or weak side linebacker. He will fill in for Sio Moore on the weak side until Moore is fully recovered from offseason hip surgery. But after that, the team will have to figure out how they want to utilize their personnel with Smith, Moore, and Mack all in the lineup.
Should Smith impress while in relief of Moore, it may be best to keep him on the field at outside linebacker and move Mack to defensive end entirely.
How this plays out is dependent on how the draft plays out. If the Raiders manage to find a defensive end they like, he would be a factor in deciding which personnel presents the best group on the field.
As of right now, Oakland's starting defensive ends penciled in are Justin Tuck and Benson Mayowa.
Tuck led the team with 5.0 sacks last season with Mack second with 4.0 sacks. Mayowa took over for the injured Lamarr Woodley in week six and finished with 1.0 sack on the season.