Seattle Mariners’ Tyler O’Neill: Prospect on the Rise

The Seattle Mariners have a less-than-stellar farm system, but outfielder Tyler O’Neill has slightly altered the complexion by turning himself into a Top-100 prospect this season.

For the Seattle Mariners, drafting and identifying talent hasn’t been much of a problem, in part because they had so many early selections over the last five or so seasons. Dustin Ackley was the consensus #2 pick behind Stephen Strasburg. Taijuan Walker could have been (and could still be) a top-of-the-rotation arm. D.J. Peterson and Alex Jackson were seen as nice picks who were likely to develop into above average bats in the future.

The problem, instead, has been developing that talent (apart from Kyle Seager), either once they get to the majors, or before they even get there. Ackley and Walker were revered throughout the minors but haven’t succeeded at the majors. Peterson and Jackson have had up and down minor league careers so far, surging lately but being disastrous last season.

These occurrences have left Seattle’s farm system fairly barren, being ranked among the bottom 5-10 by just about everyone. But they may have found a savior, at least as much as a single player can save an entire farm system. That man is 21-year-old outfielder Tyler O’Neill.

O’Neill was drafted in the third round out of Garibaldi Secondary School in British Columbia, Canada back in 2011. His tremendous raw power was obvious even then, but he was overshadowed by D.J. Peterson and Austin Wilson, two other power bats that Seattle took ahead of him. So far, though, O’Neill has outplayed both of them quite substantially.

O’Neill spent most of his first “full” year (I put full in quotes because he only played 61 games in total) playing for the Clinton LumberKings of the A-ball Midwest League. In his 57 games there, O’Neill batted .247/.322/.466 with 13 home runs and a 124 wRC+. As you can see by the home run pace — 13 over 57 games comes out to over 30 for a full minor league season — the power didn’t disappoint. But the .247 average along with a 32.2 percent strikeout rate were cause for concern, and showed that the contact issues were also very real.

He did take some steps forward last year, slashing .260/.316/.558 with 32 home runs and a 128 wRC+ in 106 games with High-A Bakersfield, but many of his problems were still present. His strikeout rate was still at 30.5 percent, he hit just .260, and he actually walked even less, down to 6.5 percent from 8.2 percent in 2014. The power may have increased, but no one doubted his power in the first place, so it didn’t do much to alleviate concern.

This season, though, has been different. O’Neill has absolutely demolished the Double-A Southern League, making huge strides with his contact issues in the process. He is currently hitting .308/.376/.552 with 17 home runs and a 162 wRC+. What’s more:

It’s one thing for some 25-year-old to post those numbers — as is the case with the other four above– because it’s likely due, at least in part, to his age, being more advanced than the competition (the average age in the Southern League is 24). But at barely 21, O’Neill is at an age where a lot of people would still be in college, potentially a year away from even being drafted.

Of course, the biggest thing here is the major progress in his average and strikeout rate. He is up over .300, and his K-rate is down at a much more manageable 24.2 percent. What’s more, he is walking more than he ever has, at 9.5 percent, which is a nice trait to have, especially if you aren’t a great contact hitter, that often goes overlooked in traditional scouting.

More from Call to the Pen

• Philadelphia Phillies, ready for a stretch run, bomb St. Louis Cardinals
• Philadelphia Phillies: The 4 players on the franchise’s Mount Rushmore
• Boston Red Sox fans should be upset over Mookie Betts’ comment
• Analyzing the Boston Red Sox trade for Dave Henderson and Spike Owen
• 2023 MLB postseason likely to have a strange look without Yankees, Red Sox, Cardinals

The power is down a touch from last year, as his 17 home runs would pace out to about 21 if he had the same number of plate appearances as last year, but it’s a tougher league, and the ball doesn’t fly as much as it does in the Cal League. He’s also added more doubles where he’s lost some home runs, so that helps even it out some. Plus, he’s second among qualified Southern League hitters in ISO (isolated power), so saying his power dropped is true, but also pretty misleading.

These improvements earned O’Neill the #45 spot on Baseball America’s Midseason Top-100 Prospects, after not even appearing on the preseason list, and I would imagine it will jolt him to the top of most Mariners prospect rankings as well.

Obviously there’s no guarantee this sticks, but the sample size isn’t insignificant, and he hasn’t shown many signs of stopping. June was his worst month so far, slashing .269/.331/.481, but that’s still not bad, and really just looks like the former version of himself. Instead of that being his average, that’s where he reverts to when he struggles. Not a bad situation.

And, though it’s only a six-game sample, he has been back to his dominant self in July, hitting .318/.464/.727. I haven’t even mentioned that O’Neill profiles as an average or better defender with a plus arm in a corner outfield spot, something that can be pretty rare for guys with so much power, many of whom end up either hurting their team out there, or moving in to first base.

Next: Was Chris Sale the Right Choice to Start for the AL?

The second half of the year will tell us a lot about how real this transformation is. But if it sticks, expect O’Neill to for sure start next year in Triple-A, if he doesn’t make his way up there this season, and have a shot at joining the Mariners in late 2017.