Seasoned prospects, young arms developing at M's mini camps

Seasoned prospects, young arms developing at M's mini camps

After bringing in a new front office regime late last season, including a new director of player development in Andy McKay, the Mariners, as a system, took a step in the right direction in 2016.

As a whole, the Mariners' stateside teams led organized baseball with a cumulative .572 winning percentage, and two of those teams, the Rookie-level AZL Mariners and Double-A Jackson, won their league's titles. In fact, all Seattle's qualified for the postseason.

In the wake of their system-wide success, the Mariners have decided not to field a team in the fall instructional league in Arizona this year and will instead host a series of mini-camps throughout the offseason. Beginning next Monday, players will report to the team's facility in Peoria, Ariz., and continue to do so once per month for small group work that covers everything from the cultural and mental sides of the game to bunting and baserunning.

"We spent about a week last offseason doing something similar with our guys, laying out to our hitters what their goals should be and what we want them to accomplish each time they're in the batter's box, and everyone just ran with it this year," McKay said. "We want to expand on that this year, and this will allow us to work with all our players and get everyone on the same page."

Former first-rounders back on track

Mariners No. 8 prospect and 2013 No. 12 overall Draft pick D.J. Peterson put himself on the fast track to the Major Leagues by hitting 31 homers with 111 RBIs in his first full season, only to take a considerable step back in his return to the Southern League in 2015. He finally righted the ship this year with a strong showing back at Double-A Jackson --- in his third straight year at the level -- and then continued to make strides following a promotion to Triple-A.

"He's a guy who's in the best spot he's ever been in for his career," said McKay of the 24-year-old Peterson, who posted a .745 OPS and slugged eight homers in 46 Triple-A contests before a broken left finger ended his season in late August.

On the other side of the ball, it may not be long until Peterson, who began his pro career as a third baseman before shifting to first base on a full-time basis this year, can add "outfielder" to his defensive resume.

"He had a few reps out there, and I think you'll see us continue to try to increase his versatility and give him as many pathways to the Major Leagues as possible," said McKay. "He's at that point where you have to create as many options as you can. So as he's figured things out at the plate, we've had to consider different ways we might be able to get him into the lineup."

The Mariners held back 2014 No. 6 overall Draft pick Alex Jackson (Mariners' No. 6) in extended Spring Training to start the season so that he could mature both on and off the field. After checking all the necessary boxes, he finally debuted with the Class A Clinton Lumberkings -- also where he began his 2015 campaign -- in mid-May and proceeded to hit .243/.332/.408 over 92 games, with a career-high 11 home runs, 20 doubles and 55 RBIs. Jackson performed particularly well in the second half, as he overcame a slow start to post a .261/.357/.417 battling line over his final 62 games.

"Baby steps count," said McKay, "And there were a lot of good things that happened for Alex this year. He showed some decent power numbers and played the outfield very well. Most importantly, he stayed healthy and gained a lot of experience with a full-season affiliate while playing for a very good team.

"Like [Peterson], Alex's career is in the best place it's ever been right now, and whether it's next year or the year after, at some point there's going to have a massive breakthrough. He showed glimpses of it this summer, and at times fairly consistently."

Arms on the rise

Jackson wasn't the only Lumberking to make strides in 2016. Nick Neidert and Luiz Gohara, Seattle's top two pitching prospects, both dominated during their time with Clinton and were major reasons that the club finished second in the Midwest League.

The Mariners' first-overall selection in the second round of the 2015 Draft, Neidert (Mariners' No. 4), 19, proved to be one of the more advanced hurlers in the system as he pitched to a 2.57 ERA and a 0.97 WHIP in 91 innings across 19 starts.

"Nick is a mentally advanced pitcher who goes about his business like someone who has a future in the big leagues," said McKay of the young righty. "He's as mature as you're going to find for that age, and the way he works and the way he pitches - everything has a purpose and plan to it."

As for Gohara (Mariners' No. 5), the 20-year-old, Brazilian left-hander, after several inconsistent campaigns to begin his career, posted a stellar 1.81 ERA in 13 starts, compiling 81 strikeouts against 23 walks in 69 2/3 innings.

"Luiz has put himself on everyone's radar with his fastball command and velocity as well as his slider," McKay noted. "It was exciting to see him start putting things together career-wise, because up to that point it hadn't gone the way he wanted. It was definitely a breakout season for him.

2016 Draftees impress

Having already landed Golden Spikes Award winner Kyle Lewis with the No. 11 overall Draft pick, the Mariners continued to add hitters to their system with the selection of prep third baseman Joe Rizzo in the second round (No. 50 overall). Regarded by scouts as one of the better high school hitters in his class, Rizzo (Mariners' No. 9) lived up to that billing this summer in his pro debut as he batted .291/.355/.392 over 39 games in the Arizona League.

"He's just a very mature high school hitter," said McKay of Rizzo. "You just watch him around the cage doing his work, watch him between pitches, watch him in the dugout, and you get the sense that he's a guy who really knows what he's doing."

The Mariners also received encouraging early returns from fourth-rounder Thomas Burrows and sixth-rounder Brandon Miller, as the duo helped to form an impressive pitching staff at Class A Short Season Everett.

One of the top Division II hurlers in the country during the spring, Miller built on his strong collegiate career at Millersville with a smooth transition into the professional ranks. In 14 appearances (13 starts) for Everett, the 21-year-old righty recorded a 2.72 ERA with a 0.96 WHIP and 51-7 strikeout-to-walk ratio in 56 1/3 innings.

Burrows, 22, established a new career saves record (30) during his junior year at Alabama and then added six more in his pro debut with Everett. Overall, the southpaw logged a 2.55 ERA and racked up 37 strikeouts in 24 2/3 innings spanning 20 appearances.

"We had a pretty good group of college pitching on our Everett team," McKay reflected, "and they all did what we thought they we're going to do. [Miller and Burrows] are both strike-throwers and somewhat polished guys, and that's what we were looking for in the Draft."

Mike Rosenbaum is a reporter for MLB.com. Follow him on Twitter at @GoldenSombrero. This story was not subject to the approval of Major League Baseball or its clubs.