He earned a medical redshirt to preserve a year of eligibility, and the following season, started the first four games at weakside linebacker before again suffering a season-ending injury, this time a ruptured left Achilles tendon.

[4] On January 24, 2015, Hicks played in the Reese's Senior Bowl and recorded five combined tackles to help Tennessee Titans head coach Ken Whisenhunt's North team defeat the South 34–13.

[5] On March 24, 2015, Hicks attended Texas' pro day, along with Malcom Brown, Quandre Diggs, Jaxon Shipley, Geoff Swaim, Cedric Reed, Mykkele Thompson, and ten other prospects.

[6] At the conclusion of the pre-draft process, Hicks was projected to be a fourth or fifth round pick by NFL draft experts and scouts.

Head coach Chip Kelly named him the backup inside linebacker behind starters Kendricks and Ryans to begin the regular season.

The following week, Hicks made seven solo tackles, notched his first career sack, and forced a fumble in a 20–10 loss to the Dallas Cowboys.

[16] He earned more snaps on defense after linebackers Mychal Kendricks suffered a hamstring injury and Kiko Alonso injured his knee in the first half of the game.

[21][22] In Week 6, Hicks made his third career start in place of Mychal Kendricks and collected a season-high ten solo tackles in a 27–7 victory over the New York Giants.

On November 8, 2015, he made seven combined tackles, deflected a pass, collected an interception, and scored his first career touchdown during a 33–27 overtime victory at the Dallas Cowboys.

[25] Hicks finished his rookie season with 50 combined tackles (43 solo), three pass deflections, two interceptions, a sack, and a touchdown in eight games and five starts.

Hicks entered training camp slated as the starting middle linebacker, but saw competition from veteran Stephen Tulloch.

On October 23, 2016, he collected a season-high 11 combined tackles, defended two passes, and sacked Minnesota Vikings quarterback Sam Bradford in the Eagles' 21–10 victory.

In Week 9, he collected seven combined tackles, two pass deflections, and intercepted Giants' quarterback Eli Manning to set up a potential game-winning touchdown in their 28–23 loss.

On January 1, 2017, Hicks made five solo tackles, deflected two passes, and had his first multi-interception game after picking off Mark Sanchez two times during a 27–13 win over the Cowboys.

He started the Eagles' season-opener against the Washington Redskins and recorded seven combined tackles and recovered a fumble from quarterback Kirk Cousins during a 30–17 victory.

During a Week 7 matchup against the Redskins, Hicks suffered a season-ending achilles injury and was placed on injured reserve on October 31, 2017.

[35] In week 2 against the Tampa Bay Buccaneers, Hicks recorded a team high 9 tackles and recovered a fumble forced by teammate Malcolm Jenkins on wide receiver Mike Evans and returned it 13 yards during the 27–21 loss.

[46] In week 10 against the Buccaneers, Hicks recorded a team high 9 tackles and intercepted a pass thrown by Jameis Winston during the 30–27 loss.

[48] In week 16 against the Seattle Seahawks, Hicks recorded 6 tackles and recovered a fumble forced by teammate Chandler Jones on wide receiver David Moore during the 27–13 win.