Also named from the Mariners were infielder Patrick Kivlehan, catcher John Hicks and right-handed pitchers Matt Anderson, Matt Brazis and Stephen Landazuri. It will be Kivlehan's second AFL season, as he played for the Peoria Javelinas last year.
Peterson was expected to play in the AFL last season until he was hit in the face with a pitch in August and sidelined for the remainder of the year.
"I'm looking forward to being challenged and facing good competition," Peterson told MLB.com. "It gives me a chance to see what I might be able to see one day in the big leagues."
It's also a bit of a homecoming for Peterson, who has split his first full season between the Class A Advanced California League and the Double-A Southern League. The Arizona native will get the chance to play in very familiar surroundings, while sharing an apartment with his younger brother Dustin (No. 12 on the Padres' Top 20) and his cousin Nate Causey, an Arizona State product selected by the Rockies in the 19th round of this June's Draft. Both will be in Arizona for instructional league play for their respective organizations.
"I've lived in Arizona my whole life," Peterson said. "It's where I played baseball almost my whole life. I'm looking forward to being home."
Peterson has hit .254 with 10 home runs and 31 RBIs in 52 games since being promoted to Double-A Jackson after batting .326 with 18 homers and 73 RBIs in 65 games for High Desert.
Kivlehan also was bumped up to Jackson midseason and is batting .301 with 11 homers and 65 RBIs in 98 games. Hicks started the year in Jackson (.296, 3 HRs, 27 RBIs in 53 games) and is now at Triple-A Tacoma where he's hit .284 with two homers and 19 RBIs in 24 games.
Landazuri and Brazis are currently pitching for Jackson. Landazuri has spent the full season in Double-A and is 6-5 with a 3.94 ERA in 18 starts, while Brazis is 1-1 with a 1.86 ERA in 14 relief appearance for Jackson after going 3-0, 2.97 ERA in 23 outings for High Desert.
Anderson started the year in Jackson and was 3-5 with a 5.16 ERA in 13 starts and now has gone 3-2 with a 4.91 ERA in 12 games (seven starts for High Desert).
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. Adam Lewis is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.