SEATTLE — Third baseman D.J. Peterson continues to validate his status as the Mariners’ top non-pitching prospect.
Baseball America selected Peterson (paid link) as the No. 8 prospect in the Double-A Southern League on Monday after previously citing him as the No. 10 prospect in the Hi-A California League.
Peterson, 22, opened the season at Hi-A High Desert before getting promoted in late June to Double-A Jackson. He batted a combined .297 in 123 games with 31 homers and 111 RBIs.
“Peterson can turn around any pitcher’s fastball with a quick, buggy-whip swing the produces consistent loud contact,” Baseball America reported. “He doesn’t swing and miss excessively for a hitter with plus power.”
Baseball America also identified infielder Ketel Marte as the No. 15 prospect in the Southern League. Marte, 21, batted .302 with two homers and 46 RBIs in 109 games at Jackson before batting .313 in 19 games at Triple-A Tacoma.
“Marte has feel for contact from both sides of the plate,” Baseball America reported, “with a handsy swing that enables him to manipulate the barrel and line the ball to all fields.
“He won’t hit for more than gap power, but plus speed will ensure he racks up his share of doubles and triples to go with a healthy quantity of stolen bases.”
Dodgers shortstop Corey Seager, the brother of Mariners third baseman Kyle Seager, was picked by Baseball America as the Southern League’s No. 3 prospect. Cubs third baseman Kris Bryant was No. 1.
The Mariners recently chose Peterson, their first-round pick in 2013, as their co-minor-league player of the year with first baseman/outfielder Jordy Lara.
Peterson is currently playing for the Surprise Saguaros in the Arizona Fall League, where he is 3-for-9 with four walks in three games.