Peterson's older brother, D.J., whom the Mariners selected with the 12th overall pick, agreed to terms with the team Thursday. D.J. Peterson, a third baseman from the University of New Mexico, was a player whom the Padres had a lot of interest in.
Dustin Peterson agreed to an undisclosed bonus, though it was above-slot for that pick ($1.082 million).
The Padres were very excited the younger Peterson was available at No. 50.
Peterson, who was recommended by area scout Dave Lottsfeldt, hit .540 with 11 doubles, six triples, 10 home runs and 39 RBIs this spring.
"He's an offensive shortstop who we think had one of the better high school swings in the Draft. We see him playing somewhere in the infield and hitting for power," Padres scouting director Billy Gasparino said.
Peterson figures to being playing soon with the team's entry in the Arizona League.
The Padres selected Mississippi State outfielder Hunter Renfroe with the 13th overall pick. He is playing in the College World Series.
The Padres have signed no fewer than 24 of their 41 selections in the this year' Draft.
Also recently, the team had signed right-hander Travis Remillard (13th round) and outfielder Marcus David (24th).
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.