In their first season under Jerry Dipoto, the Seattle Mariners finished second in the American League West. It was the first time since 2007 the Mariners had reached such heights within the division. What’s more is it was just the third time the Mariners had finished within 10 games of the division winner since 2001 -- you might remember that as the season they won 116 games, or, if you’re a Seattle fan, as the year of their most recent playoff appearance. Woof.

Dipoto has spent all winter retooling the Mariners’ roster. Will it be enough for the M’s to get over the hump and experience postseason baseball for the first time in a long time?

The vitals

The clock is ticking

Here’s the oddest thing about these Mariners: Though they haven’t reached the postseason in nearly two decades, their competitive window is closing.

Seattle’s core comprises Robinson Cano, Nelson Cruz, Kyle Seager, and Felix Hernandez. Seager is the baby of the four -- he’ll turn 30 in November. Think hard enough and you can form legitimate reasons why the others are attrition risks. To wit: Cano is a second baseman, and they seldom age well; Cruz is a slugger, and they seldom age well; Hernandez is a pitcher and a king, and neither tends to age well. You get the point.

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Is this the year Felix Hernandez experiences playoff baseball? Kelvin Kuo, Kelvin Kuo-USA TODAY Sports

While performance-related decline is a tangible concern with everyone in the group, job security is not. Cruz, who is under contract through the 2018 season, is the only one who can hit free agency before 2020. Predictably, each of those fellers is getting paid. The Mariners’ payroll will open the season around $150 million -- about a third of that is being deposited into Cano and Hernandez’s bank accounts. Factor in the money due to Cruz and Seager, and Dipoto’s financial flexibility is limited.

Committing that much to four players in or nearing their mid-30s is a problem in general, and it doesn’t help that Dipoto’s offseason additions were all short-term in nature: Jarrod Dyson and Danny Valencia are pending free agents; Yovani Gallardo could be; and Jean Segura and Drew Smyly, the long-term gets of the crew, are a year away from being labeled the same.

Put simply: The Mariners’ best players are getting old, meaning their contracts are becoming more burdensome, meaning they’re less likely to be able to retain their supporting cast, meaning they’re heading toward an uncertain and -- in all likelihood -- unpretty future, meaning they better win while they have the chance, meaning 2017 is a pivotal year in Seattle.

Improved?

Okay, so maybe this is actually the oddest thing about these Mariners: They overhauled their roster during the winter, yet it’s unclear if the finished product is much better than the original.

Dipoto consummates trades at the same pace most people consume Sour Patch Kids -- quickly, by the sugary, colorful handload. During the winter, that meant adding Carlos Ruiz, Jean Segura, Drew Smyly, Jarrod Dyson, Yovani Gallardo … take a breath ... Mitch Haniger, Danny Valencia, and Chris Heston. Phew. Oh, and those are just the winter trade acquisitions who are projected to crack the Opening Day roster --  it’s possible that Taylor Motter, Rob Whalen, Shae Simmons, James Pazos, and Zac Curtis could break through in addition to and/or instead of some of the aforementioned players. Dipoto’s high-frequency trading left the Mariners with a roster that, for better or worse, seemingly has greater variance than last year’s bunch.

Nearly every aspect of the roster has an unusually wide outcome band. Take the outfield. Pairing two well-above-average gloves in Leonys Martin and Dyson with Haniger -- who should be a plus in a corner -- ought to result in a top-notch defensive unit. Yet it’s possible each of the three are below-average hitters. That would be a difficult outcome for most teams to stomach, let alone one who has question marks at first base, catcher, and shortstop -- hey, Segura could provide Seattle with its best overall six-spot play since Alex Rodriguez … or he could not. Employing Cano, Cruz, and Seager gives the Mariners some wiggle room to take risks and sacrifice offense for defense, but as constructed, they’re flirting with having a dangerously thin lineup.

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James Paxton could be a key for the M’s rotation.  USATSI

A dangerously low floor for the rotation

Perhaps the thinness of the lineup would be tolerable if the Mariners rotation didn’t feature significant downside as well, starting at the top. Hernandez hasn’t pitched at ace levels since 2014. Last season snapped his decade-long run of making 30-plus starts, and also brought with it a career-worst 1.88 strikeout-to-walk ratio. The news is hardly better for Seattle’s other rotation stalwart, Hisashi Iwakuma, who is entering his age-36 campaign after posting career-lows in ERA+ and strikeout rate. There’s no promise Hernandez and Iwakuma perform better in 2017 than they did in 2016 -- realistically, they might both pitch worse.

The Mariners are poorly positioned to handle that scenario. James Paxton’s upside is as tantalizing as his durability woes are frustrating. To his credit, he topped 25 starts between the majors and minors last season for the first time since 2013. Compounding matters is how neither Gallardo nor Smyly is a bastion of health. Gallardo started 23 times in 2016, all the while showing uncharacteristically poor control. Smyly took the ball 30 times, but gave up nearly two home runs per nine after missing significant time the year prior due to a bum shoulder. Ruh roh.

If -- okay, when -- one (or more) of those starters misses time, the M’s will turn to some shaky depth. Cuban import Ariel Miranda, gained in the Wade Miley salary dump, is at the front of the line. Scratch deeper and you draw the likes of Heston, Whalen, Dillon Overton, and Cody Martin -- essentially a collection of trade throw-ins and waiver claims with vaguely familiar names. Or, if the Mariners are feeling frisky, there’s Andrew Moore, whose modest No. 4 starter ceiling obscures that he’s arguably the system’s best pitching prospect.

On that note ...

Seriously, the clock is ticking

Dipoto is known for his boyish good looks, for his predilection with oddball relievers, for his ability to find undervalued trade assets. He is not known for building or maintaining a farm system. Tyler O’Neill and Kyle Lewis -- each potential regulars in the outfield -- are the Seattle prospects to keep in mind. Otherwise, Dipoto is going to have to find external answers to his questions.

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Edwin Diaz tends to prompt celebratory handshakes.  USATSI

Closing on a high note

Mariners fans have every reason to be conflicted about this roster. There’s enough star power and potential here to precipitate a playoff run. Yet there’s also enough plausible downside to foresee a disappointing fourth- or fifth-place finish. This figures to be a divisive team until the fall. However, if there’s one thing on which everyone can agree, it’s that the M’s could have a thrilling bullpen.

There are three reasons for that. Their names are Edwin Diaz, Shae Simmons, and Tony Zych.

Diaz ascended last season from middling starter prospect to one of the game’s top young relievers. He struck out 88 batters in 51 innings, showcasing a power fastball-slider combination en route to taking over closing duties. Simmons and Zych aren’t as well-known, but each could improve his Q rating in 2017.

Prior to missing nearly all of the past two seasons due to Tommy John surgery, Simmons looked like he would become Craig Kimbrel’s primary setup man in Atlanta -- fitting, given Simmons kinda looks like a mini-Kimbrel, complete with an upper-90s fastball and quality slider. Zych, meanwhile, pairs his big heat and slider with a short, deceptive arm stroke. Provided Simmons and Zych do a better job of staying on the mound, they could form a devastating trio with Diaz.

Probable lineup

  1. Jarrod Dyson, LF
  2. Jean Segura, SS
  3. Robinson Cano, 2B
  4. Nelson Cruz, DH
  5. Kyle Seager, 3B
  6. Mitch Haniger, RF
  7. Dan Vogelbach, 1B
  8. Mike Zunino, C
  9. Leonys Martin, CF

Bench: C Carlos Ruiz; CI/OF Danny Valencia; UTL Shawn O’Malley; OF Guillermo Heredia

Probable rotation

  1. Felix Hernandez (R)
  2. Hisashi Iwakuma (R)
  3. James Paxton (L)
  4. Yovani Gallardo (R)
  5. Drew Smyly (L)

Probable bullpen

Diaz will be the closer. The aforementioned Zych and Simmons could, at some point, become his primary setup men. It’s more likely that a veteran combination -- perhaps of Steve Cishek, Nick Vincent, Marc Rzepczynski,and Casey Fien -- enter the season as the main bridge options.

SportsLine projection: 80-82, third place in the AL West