Mercer (Lacey, Wash. / Timberline HS) was selected in the fifth round, the 159th overall pick, by the Diamondbacks. The junior, who was an honorable mention All-Pac-12 Conference selection, finished the 2018 season with a 13-16 career record and a 3.77 ERA in 46 appearances. In three seasons with the Ducks, Mercer started 35 games, the sixth most in Oregon history. He fanned 176 batters in 217 innings, with both the strikeouts and innings pitched ranking ninth all-time at Oregon. During the 2018 season, Mercer went 5-7 with a 4.16 ERA. He led the Ducks with 88.2 innings pitched while striking out 86, ninth all-time at Oregon.
Mercer is the 30th Oregon pitcher picked in the MLB Draft since the sport returned in 2009. Of those 30, Mercer is the 10th drafted in the top five rounds and one of 16 drafted in the top 10 rounds. He is also the sixth Oregon player drafted by the Diamondbacks. Arizona drafted catcher Tim Susnara in the eighth round last season, shortstop Mark Karaviotis in the 19th round in 2016, pitcher Brando Tessar in the 25th round in 2014, closer Jimmie Sherfy in the 10th round in 2013 and infielder Danny Pulfer in the 19th round in 2011.
Oregon has now had 45 players drafted since 2009 with a total of 66 Ducks drafted all-time.