In 47 relief appearances between the New York Yankees and Seattle Mariners last season, Warren went 3-2 with a 3.14 ERA (18 ER, 51.2 IP), 1.32 WHIP and 9.06 SO/9.0 IP ratio (52 strikeouts). Over the first three months of the season, Warren had the sixth-lowest ERA among all American League relievers (1.35, 3 ER, 20.0 IP). The 31-year-old posted a 4.08 ERA (8 ER, 17.2 IP) in 13 games at Yankee Stadium, as opposed to a 2.64 ERA (10 ER, 34.0 IP) at all other Major League ballparks in 2018 (34 games).
Over parts of seven Major League seasons, Warren is 26-23 with six saves and a 3.42 ERA (176 ER, 463.2 IP), 1.22 WHIP, 0.91 HR/9.0 IP ratio and .235 opponents average in 298 games (21 starts). Since 2014, he has the third-most scoreless relief appearances of at least 1.1 innings among all Major League pitchers (68). Warren was originally selected by the Yankees in the fourth round of the 2009 First-Year Player Draft out of the University of North Carolina, where he posted the second-most wins in school history (32) and helped lead the Tar Heels to the College World Series in three consecutive seasons (2006-08).
Warren will wear No. 17.