[5] Head coach Jack Del Rio named Morrow the primary backup weakside linebacker, behind Cory James, to begin the regular season.

On October 15, 2017, Morrow earned his first career start at middle linebacker against the San Diego Chargers after Marquel Lee sustained an ankle injury the previous week.

[8] On December 31, 2017, the Oakland Raiders officially announced their decision to fire head coach Jack Del Rio after they finished the 2017 NFL season with a 6–10 record.

Head coach Jon Gruden named Morrow the backup strongside linebacker, behind Tahir Whitehead, to begin the regular season.

[11] Morrow entered training camp as a backup outside linebacker after the Raiders signed free agents Vontaze Burfict and Brandon Marshall.

In Week 5, Morrow earned his first start of the season, replacing an injured Marquel Lee, and recorded four solo tackles, deflected a pass, and made his first career interception as the Raiders defeated the Chicago Bears 24–21.

Morrow intercepted a pass attempt by quarterback Chase Daniel, that was intended for wide receiver Allen Robinson, and returned it for an 11-yard gain in the first quarter.

[16] In Week 2 against the New Orleans Saints on Monday Night Football, Morrow led the team with 7 tackles and recorded his first interception of the season off a pass thrown by Drew Brees during the 34–24 win.