[9] Having graduated with a double major in Sociology and Science, Technology and Society, and a minor in Education in December 2017,[10] Phillips decided to forgo his last year of eligibility and enter the 2018 NFL draft.

[12] On January 4, 2018, Phillips officially announced his decision to forgo his remaining year of eligibility and enter the 2018 NFL draft.

He was eligible to return as a fifth-year senior after missing the majority of his sophomore season due to an ankle injury he sustained in the season-opener.

[14] On January 27, 2018, Phillips played in the 2018 Reese's Senior Bowl and was part of Denver Broncos head coach Vance Joseph's North team that lost 45–16 to the South.

[16] On March 27, 2018, Phillips participated at Stanford's pro day, but opted to stand on his combine numbers and only performed positional drills.

At the conclusion of the pre-draft process, Phillips was projected to be a second round pick by NFL draft experts and scouts.

In his second year, Phillips recorded his first career sack against the New York Giants, taking down Eli Manning during a 28–14 Bills win.