The Seattle Mariners aren’t the young club they were a few years ago, but they remain one with the upside of a developing talent in his early twenties. Developing talent is exactly the reason why they remain a team with big upside.

The Mariners have become an older team the last few years. They’ve gone from ‘Youth Movement’ to ‘Aggressive’ and that’s landed them two significant thirty-somethings in Robinson Cano and Nelson Cruz. Adding Melky Cabrera or Alex Rios to the mix means yet another player over 30 years of age on the 25-man roster.

The likes of Brad Miller, Chris Taylor, Dustin Ackley, Mike Zunino and Logan Morrison remain, however, as do James Paxton, Taijuan Walker and Roenis Elias. All of the aforementioned players likely have their best baseball in front of them — some more obviously than others. Kyle Seager may not be done improving his game, either, and he’ll be just 27 all of 2015.

For me, it all starts with Miller.

Despite the general belief that he can’t play shortstop, Miller absolutely can, and has done so at acceptable levels. He does need to cut down on the mistakes made on routine plays, but he’s more than adequate at the position thanks to arm strength, good range to his right and improving range up the middle. Perhaps an adjustment in his arm slot can help his throwing accuracy.

Miller, a left-handed batter, possesses big-time ability at the plate. He struggled for much of 2014, but found his groove later, and it wasn’t just a small sample size. From June 1 through the end of the season, Miller posted a .265/.326/.447 triple-slash despite an awful month of July. His line drive rate rocketed to 26 percent the second half of the season and and after 64 strikeouts in 169 plate appearances (24.3 %) in through June, the former second-round pick whiffed just 31 times over his final 148 plate appearances (20.9 percent) as he showed a more aggressive approach — which back to his root skills as a hitter.

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Miller’s upside at the plate could ultimately allow for him to move to another position, perhaps left field, yet still be a position value offensively. [This scenario makes sense only if the Mariners find a clear, everyday answer at shortstop. Perhaps that’s Chris Taylor, ultimately, but that equation remains on the blackboard without a definitive result as 2015 nears.]

Zunino broke the team record for home runs by a catcher but had more extra-base hits than singles while striking out 158 times and drawing just 17 walks. Zunino isn’t likely to be the type to walk a lot, but his batting average on balls in play of .248 is likely to bounce back to the .260s — .267 in 52 games and 193 PAs in 2013 — which brings with it a much more palatable batting average and on-base mark, and that doesn’t even include the organic expectation that the 23-year-old will simply be better after 669 trips to the plate — and counting — in the big leagues, particularly considering he received just 419 plate appearances in the minors.

Ackley doesn’t bring as much upside — he’s not going to turn into the originally-projected borderline all-star bat most believed he’d be back in 2009 when he was the consensus No. 2 player in the class — but he slugged over .500 in 205 plate appearance in July and August and his slight mechanical adjustments made over the summer may allow him to produce more of the same in 2015.

 Clearly Paxton can pitch and while he’s not an ace, he possesses frontline stuff and has progressed with his delivery allowing him to throw strikes with more consistency. Ultimately, Paxton may very well be the No. 2 starter behind Felix Hernandez, and at times he was the second-best starter on the roster in 2014, even though Hisashi Iwakuma was again terrific.

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Walker enters 2015 still unproven, but significant progress was seen in terms of fastball command and at times late in the year his curveball flashed average or better. The 22-year-old remains a high-end young talent with a chance to be a No. 2 starter down the road, and there is no reason he can’t be league average or so in 2015 as he pitches in the back end of the club’s rotation.

Elias was solid in his first season in the big leagues and despite some ups and downs along the way, as well as a somewhat advanced age for a rookie, there’s upside left in the 26-year-old. He has the makings of an out-pitch curveball, he’s athletic and the development of his changeup in ’14 was essential for his future.

There probably isn’t a lot more room for development in Seager’s game, but incremental progress in areas such as contact rates, facing left-handed pitching and using the backside of the field all could result in the 27-year-old going from solid everyday player to perennial all-star.

Taylor doesn’t bring the type of offensive upside Miller does, but he works counts, draws some walks and can reach the gaps, all while playing an average to above-average shortstop.

The Mariners aren’t going to luck out and have each of the above players max out their natural, physical abilities, but there is a reasonable chance one of them does, and there’s a good chance a few of them get to a point where they are average or better core type major leaguers.

The above group is a big reason why the Mariners’ window isn’t just 1-2 years deep. Where some of the veterans fade a little as they age, the younger players can pick up some slack, and that goes for the longer-term prospects, too, such as D.J. Peterson, Ketel Marte, Gabby Guerrero and Alex Jackson.

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The M’s are focused on 2015, and to a lesser extent 2016. But there are plenty of reasons to buy into them for ’17 and beyond, too, and if the right talents bust through this next season, we might be watching the club place 95 wins in their rear-view mirror. And in doing so resetting the bar to heights the organization hasn’t seen in more than a decade.

Jason A. Churchill

Churchill founded Prospect Insider in 2006 after getting his start at He spent several years covering prep, college and pro sports for various newspapers, including The News Tribune and Seattle PI.

Jason spent 4 1/2 years at ESPN and two years at CBS Radio prior to joining HERO Sports in July, 2016.

Find Jason's Mariners podcast, Baseball Things, right here and follow him on Twitter @ProspectInsider.