Astin played collegiately at Arkansas and was a key member of the Razorbacks squad that made it to the College World Series in 2012. He led the '12 team with 11 saves, amassing a 1.99 ERA and 61 strikeouts while pitching in a team-high 32 games.
The right-hander moved into Arkansas' starting rotation this past season, posting a 1.79 ERA to go with his 4-4 record and 74 strikeouts over 90 2/3 innings.
Brewers scouting director Bruce Seid said the team would send Astin out as a starter to begin his pro career, but left open the possibility of moving him to relief later on.
David Villavicencio is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.