Throughout training camp, Brown competed for a roster spot against Kerry Taylor, LaRon Byrd, Jarrett Dillard, Robert Gill, Dan Buckner, Charles Hawkins, and Robby Toma. He earned the spot as the fourth wide receiver on the depth chart to begin the regular season after beating out veterans Kerry Taylor, Mike Thomas, Dan Buckner, and Charles Hawkins. He began the season behind Larry Fitzgerald, Michael Floyd, and Andre Roberts. Brown made his professional regular season debut in the Arizona Cardinals’ season-opener at the St. Louis Rams and caught a 14-yard pass during their 27–24 loss. On October 17, 2013, Brown caught a season-high three passes for 30-yards and scored his first career touchdown during a 34–23 loss against the Seattle Seahawks in Week 7. Brown caught his first career touchdown reception on an eight-yard pass during the fourth quarter. Brown finished his rookie season in 2013 with 11 receptions for 140 receiving yards and one touchdown in 16 games and zero starts. He also recorded five combined tackles while appearing on special teams. During training camp in 2014, Brown competed for a roster spot as the fifth wide receiver on the depth chart against Dan Buckner, Brittan Golden, Walt Powell, Kevin Ozier, and Kelsey Pope. Head coach Bruce Arians named Brown the fifth wide receiver on the Cardinals’ depth Chart to begin the regular season, behind Larry Fitzgerald, Michael Floyd, Ted Ginn Jr., and rookie John Brown. On October 5, 2014, Brown earned his first career start during a 41–20 loss at the Denver Broncos in Week 5. On November 30, 2014, Brown made a career-high seven receptions for 75-yards as the Cardinals lost 29–18 at the Atlanta Falcons. The following week, he made two receptions for 48 receiving yards and caught a season-long 26-yard touchdown pass during a 17–14 win against the Kansas City Chiefs in Week 14. He finished the season with 22 receptions for 229 receiving yards and two touchdowns in 16 games and two starts. In addition, he finished third on the team with eight special teams tackles. The Arizona Cardinals finished second in the NFC West with an 11–5 record and earned a wildcard berth. On January 3, 2015, Brown appeared in his first career playoff game as the Cardinals lost 27–16 at the Carolina Panthers in the NFC Wildcard Game. Brown retained his role as he fourth wide receiver on the depth chart, behind Larry Fitzgerald, Michael Floyd, and John Brown. On November 15, 2015, Brown caught a season-high three passes for 38-yards during a 39–32 win at the Seattle Seahawks in Week 10.