Peterson was picked #12 overall by the Mariners in 2013, and at the time he was regarded as one of the best college power bats available after slugging 18 homers in his junior campaign at University of New Mexico. The selection of Peterson was true to Jack Zduriencik’s style of stockpiling power bats, such as Mike Zunino andAlex Jackson in Seattle, and Corey Hart, Prince Fielder, Rickie Weeks and Ryan Braun, when he was Milwaukee’s scouting director.

Peterson stands tall in the box, bat resting on his shoulder until the pitch is delivered. He’ll lift the bat off his shoulder with bat cap facing the sky and hands letter-high. A subtle toe tap initiates swing, which is compact with a short load straight back. He has a slight upper-cut to the swing that creates leverage and lift, and it manifests in above-average, over-the-fence game power.  He’s patient within the zone, at times to a fault, taking pitches many hitters would be aggressive on.  He’ll tend to fly open on pitches on the outer half and roll over some outs, but in this viewing he did make adjustments and reached outside for a pitch to hit a liner to right field later in the game.

Peterson climbed to Class A ball  in his first year as a pro before his 2013 campaign came to an end after being drilled in the jaw and being placed on the disabled list. Peterson had a rebound season in 2014 between High A and Double-A, slashing .297/.360/.552 in 123 games.  As good as 2014 was for Peterson, 2015 was the opposite, where he hit .223 between Double-A and Triple-A before his season was shortened due to an Achilles injury.

Peterson began 2016 in Double-A Jackson and for the better part of three months put up pedestrian numbers (.213/.256/.350 in April and .267/.350/.429 in May before having a torrid June, hitting .323/.391/.604, and eventually got bumped to Triple-A Tacoma on June 29. During this stretch, he started seeing the ball better, stood taller in the box (adjustment made by coaching staff in Jackson), and showed more consistency at the plate, flashing some of the raw tools which the M’s were so high on when they drafted him.

Defensively, Peterson recently made the switch to first base given that Kyle Seager is holding down third base in Seattle for the foreseeable future. Peterson showed inexperience playing the position, stretching too early for throws at times in addition to limited range and missing a few easy picks. Despite shortcomings, I think he’ll be able to play first base adequately because of his willingness to learn the nuances of the position and improve.

Peterson displayed well below average speed, running 4.50 sec. HP-1st. Doesn’t profile as base stealer, and isn’t someone who will take the extra base.

Peterson is still considered by many a top prospect for the Mariners, and he could still be an impact player for them, but I don’t think he’ll live up to the lofty expectations put on him when he was drafted. M’s fans will probably not see Peterson in Seattle in 2016, but he figures to compete for a spot in spring training next year, especially since Dae-Ho Lee is set to become a free agent at season’s end. Peterson and newly-acquired 1B/DH Dan Vogelbach could form a nice platoon in 2017 if Lee isn’t re-signed.