He played in Major League Baseball (MLB) for the New York Yankees, Chicago Cubs, Seattle Mariners and San Diego Padres.

Before beginning his professional career, Warren pitched in college baseball for the North Carolina Tar Heels.

[1] He took classes in the Kenan-Flagler Business School, and was named to the All-ACC Academic Honor Roll in consecutive seasons.

[11] In 2011, pitching for the Scranton/Wilkes-Barre Yankees of the Class AAA International League, Warren was named to the 24th Triple-A All-Star Game.

[17] He was optioned to Triple-A on June 14, 2013, after throwing six scoreless innings in the Yankees' 3–2 18-inning loss against the Oakland Athletics on the previous day.

[19] Warren earned his first save of the season on July 28, when he pitched three perfect innings to end the Yankees' 21–5 win over the Texas Rangers.

[20] Warren was inserted back into the rotation on September 15 following Nathan Eovaldi's season-ending shoulder injury, where he made three more starts to end the season.

On December 8, 2015, the Yankees traded Warren and a player to be named later (Brendan Ryan) to the Chicago Cubs for Starlin Castro.

[25] On July 25, the Cubs traded Warren back to the Yankees along with Billy McKinney, Gleyber Torres, and Rashad Crawford for Aroldis Chapman.

[28] On July 30, 2018, the Yankees traded Warren to the Seattle Mariners for international signing bonus pool space.

Warren did not play in a game in 2020 due to his recovery from Tommy John and the cancellation of the minor league season because of the COVID-19 pandemic.

[35] In 2021, Warren made 38 appearances for the Triple-A Scranton/Wilkes-Barre RailRiders, logging a 4-4 record and 3.59 ERA with 60 strikeouts in 57.2 innings pitched.

On January 19, 2023, after spending the 2022 season out of baseball, Warren announced his retirement from playing, stating that he would be open to coaching opportunities down the road.