Mayock addressed the media ahead of next week's NFL draft and praised the depth he's created at the position.
"We love what we have in Derek Carr," Mayock said, per ESPN's Paul Gutierrez. "We feel we have a very strong quarterback room."
After giving Mariota a two-year, $17.6 million contract with a maximum value of $37.5 million, the Raiders are now carrying four quarterbacks with starting experience, as DeShone Kizer and Nathan Peterman fill out the position group.
While Mayock remains complimentary of Carr, who is the supposed starter until Mayock or head coach Jon Gruden say otherwise, his actions may speak louder than words. Rarely will teams spend so much on a backup if there isn't some chance of him seeing considerable playing time.
Carr was more than serviceable last season, but the Raiders finished 7-9. He passed for 4,054 yards, 21 touchdowns and eight interceptions for a 100.8 rating—the highest mark in his professional career.
But as the franchise begins play in Las Vegas, it can hardly afford another sub-.500 season. That's where Mariota comes in.
Should Carr not continue to progress, should the team become stale, or should the play dictate it, Mariota's more mobile game would provide an alternate style on offense compared to what the team is used to with Carr.
It's a gamble nonetheless and a reality the Raiders are preparing for. There have been other, cheaper options at backup quarterback this offseason. Case Keenum signed for three years and $18 million in Cleveland, while A.J. McCarron agreed to re-sign in Houston for one year and $4 million.
There were plenty of backup-caliber players available. The Raiders paid theirs a starting salary.