Selected by the Los Angeles Rams in the fourth round (134th overall) of the 2019 NFL Draft.
Signed by the Buccaneers as an unrestricted free agent on March 23, 2023.
Has appeared in 91 career games, making 30 starts, and recording 162 tackles (13 for loss), 33 quarterback hits, 12.5 sacks and two fumble recoveries.
Has appeared in nine career postseason games, making four starts, and logging 24 tackles (four for loss), two passes defensed, two quarterback hits and 1.5 sacks.
Recorded a career-high-tying five quarterback pressures in Super Bowl LVI against the Bengals.
From 2021-22, logged 8.5 sacks, tied for 12th-most among defensive tackles over that span.
Started in the Week 1 victory over the Washington Commanders, playing 36-of-59 defensive snaps and finishing with one tackle. Took on a team-high-tying six double team blocks.
Started in the Week 2 victory at the Detroit Lions, playing 66-of-85 defensive snaps and recording one tackle and two quarterback hits.
Gaines' two quarterback hits in Week 2 were tied for his most in a single game in his career.
Started in Week 3 vs. Denver, playing 46-of-68 defensive snaps and logging two tackles.
In the Week 4 win over Philadelphia, played 25-of-57 defensive snaps and recorded one tackle.
Played 33-of-87 defensive snaps in Week 5 at Atlanta.
In the Week 6 win over New Orleans, played 21-of-70 defensive snaps.
Played 20-of-59 defensive snaps in Week 7 vs. Baltimore totaling one tackle that went for a loss. It marked his first TFL of the season.
Was Tampa Bay's highest-graded defensive player, per Pro Football Focus, in Week 7 vs. Baltimore. Earned a 67.2 overall defensive grade.
Was inactive for Week 8 vs. Atlanta and Week 9 at Kansas City.
In Week 10 vs. San Francisco, played 22 defensive snaps and finished with one tackle (for loss), one quarterback hit and 1.0 sack. His sack marked his first of the season and increased his career total to 12.5.
Appeared in a reserve capacity on defense in the Week 12 win over the New York Giants, logging 24-of-59 defensive snaps.
In the Week 13 win at Carolina, appeared in a reserve capacity on defense, playing 15-of-70 snaps.
Played 23-of-67 defensive snaps in the Week 14 win over Las Vegas, tallying two tackles.
In the Week 15 win over the L.A. Chargers, played 17-of-52 defensive snaps and logged one quarterback hit.
Played 14-of-60 defensive snaps in Week 16 at Dallas, collecting two tackles.
In the Week 17 win over the Carolina Panthers, played 15-of-47 defensive snaps and recorded two tackles.
Played 18 defensive snaps in the Week 18 victory over New Orleans, finishing with three tackles.
In the Wild Card round against Washington, played 26-of-73 defensive snaps and finished with six tackles (one for loss). Per Pro Football Focus, he was Tampa Bay's highest-graded defensive player.
Appeared in 54 games across four seasons at the University of Washington (2015-18), totaling 148 tackles (20.5 for loss), 9.5 sacks, four passes defensed, one fumble recovery and one interception.
Won the Morris Trophy in 2018, given annually to the top defensive lineman in the Pac-12.
Earned Second-Team All-Pac-12 honors and was named to the academic AllPac-12 team as a junior in 2017.