Daulton Compton Jefferies (born August 2, 1995) is an American professional baseball pitcher who is a free agent.

He has previously played in Major League Baseball (MLB) for the Oakland Athletics, San Francisco Giants and Pittsburgh Pirates.

Jefferies played college baseball for the California Golden Bears and was selected by the Athletics with the 37th overall pick of the 2016 MLB draft.

Jefferies attended Buhach Colony High School in Atwater, California, where he played as a pitcher and shortstop.

As a junior in high school, Jefferies was named the most valuable player award in the Central California Conference after pitching to a 8–0 win–loss record with a 1.26 earned run average and hitting to a .366/.480/.505 slash line.

In Jefferies's senior season, he went 10–2 with a 0.92 earned run average and a school-record 142 strikeouts, again taking home the conference's Most Valuable Player award.

[2] As a freshman for the California Golden Bears in 2014, Jefferies started 15 games, finishing the year 2–8 with a 3.45 earned run average and 58 strikeouts in a team-high 92+2⁄3 innings.

[6] He spent his first professional season with the AZL Athletics where he posted a 2.38 earned run average with 17 strikeouts in 11.1 innings pitched.