A scorer at heart, Warren added a consistent three-point shot to his repertoire during his fifth season in the league, all with the Phoenix Suns. During the 2018-19 season, Warren shot 42.8 percent from long range, which was a drastic improvement over his career mark of 28.3 percent entering the season. While his minutes and shot attempts suffered a slight dip, Warren still averaged 18.0 points per game, his fourth-straight season averaging double-figure points per contest. Warren's best month was December, in which he finished with an average of 20.7 points per contest. That included a season-high 30 point effort in a Dec. 13 win over Dallas. Unfortunately, Warren suffered an ankle injury on Jan. 22 against Minnesota, and did not play for the remainder of the season. As such, Warren was limited to 43 games, with 36 starts. Still, he finished in the top 50 in scoring average in the NBA, and would have been in the top 10 in three-point field goal percentage had he qualified. Warren also averaged 4.0 rebounds and 1.5 assists per contest, and flashed some quick hands on the defensive end with 1.2 steals per game.

The 2017-18 season was Warren's best in the NBA as he logged 33.0 minutes per game and averaged a career-best 19.6 points. By comparison, he posted just 14.4 points in the 2016-17 campaign. While the increase in offensive production was impressive, Warren continued to show he can contribute in other areas, as his 5.1 rebounds tied a career-high mark for him. Warren posted six double-doubles, including a ridiculous 40-point, 10-rebound effort in a victory over the Wizards on November 1. The 40 points were a single-game-best for the NC State product. Warren also chipped in 1.6 steals/blocks per contest. He finished with four steals on three separate occasions and three blocks three different times. Warren also drained more than 75 percent (75.7) of his foul shots for a second straight season.

Warren appeared in 66 games during the 2016-17 season, missing time due to head and foot injuries. That said, the 66 games were a career high, and he took on his biggest role to date, starting 59 games and seeing 31.0 minutes per contest. As a result, he set career marks nearly across the board, averaging 14.4 points, 5.1 rebounds, 1.2 steals and 1.1 assists. He also shot a career-high 77.3 percent from the charity stripe. Plus, he had the fifth lowest turnover rate in the league (6.1 percent). Warren set single-game career highs, as well, with 30 points and 16 rebounds. His best stretch of the season was 10 games from Feb. 15 through Mar. 11. Warren averaged 16.1 points on 11.8 shots, plus 7.6 rebounds, 1.8 assists and 1.0 blocks across 32.0 minutes. However, Warren's best single performance occurred during the second game of the season against Oklahoma. In 46 minutes, Warren recorded 30 points, nine rebounds, three steals and an assist. The Suns finished the season 24-58 and did not qualify for the postseason.

Warren's 2015-16 campaign was cut short due to a broken foot, which resulted in him appearing in only 47 games (four starts). He essentially averaged career highs across the board, notably posting 11.0 points and 3.1 rebounds per game. He also set single-game highs in points (29), rebounds (11), steals (four) and blocks (three). In addition, Warren had the second-highest offensive rating (112) on the Suns. Warren's best stretch of the season came in a seven-game period from Nov. 23 through Dec. 4. In 25.8 minutes per contest, he averaged 15.1 points on 11.9 shots per contest, plus 4.0 rebounds and 1.0 assist. He shot 57.8 percent from the field during that stretch. His best performance of the season occurred later in December during a four-point loss to the Thunder. Warren recorded 29 points (11-17 FG, 3-5 3Pt, 4-4 FT), nine rebounds, four steals and three assists with no turnovers in almost 41 minutes. He also recorded one double-double during the season. While the Suns finished the season 23-59 and out of the playoffs, Warren's play -- when healthy -- was a bright spot for the franchise.

Following two seasons with NC State, Warren was selected with the 14th overall pick in the 2014 NBA Draft by the Suns. He made his NBA debut during the seventh game of the season, seeing a little over a minute during the Nov. 9 win over the Warriors. He appeared in 40 games for Phoenix, averaging 6.1 points and 2.1 rebounds while shooting 52.8 percent from the floor and 23.8 percent from three. The 6-foot-8 forward spent considerable time in the D-League, appearing in nine games for the Bakersfield Jam over four separate assignments. There, he averaged 26.8 points on 20.0 shots, plus 7.0 rebounds, 1.6 assists and 1.6 steals in 35.4 minutes. Warren eventually worked his way into the regular NBA rotation over the final two months of the year following a trade deadline roster shake-up. Across his final 18 appearances, he averaged 8.4 points on 7.1 shots, plus 2.8 rebounds and 1.1 assists in 21.4 minutes. Warren's best game of the season was Mar. 29 during a 12-point loss to the Thunder. He posted 18 points (8-10 FG, 2-2 FT), five rebounds, two assists, two steals and one block with no turnovers in 29 minutes. The 18 points and two steals both represented career highs, while his other single-game career highs rested at seven rebounds, six assists and two blocks.