The Mariners fell short of a playoff spot last year, finishing second in the AL West, nine games behind the Rangers. It wasn't a close race, but there are reasons to be optimistic if you're a Mariners fan.

The Rangers actually sported a worse run differential than the Mariners, so Seattle wasn't as far off as the record indicates, in other words. However, 86 wins is hardly territory where you can complain about bad luck costing you.

The Mariners needed to get better in the offseason,but it's not clear that they did. They certainly got different, dramatically so in the case of their outfield, as they followed the Royals plan by beefing up the outfield defense.

They should have two new starters flanking Leonys Martin, with Jarrod Dyson and Mitch Haniger giving them essentially three center fielders patrolling the green space out in Safeco. Add in Jean Segura, and this is an athletic, sure-handed defense that should gobble up plenty of batted balls.

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The question is will they pitch well enough to make it matter? Defense can only get you so far on the margins; the guys on the mound still need to hold up their end. In order to add Segura, the Mariners shipped out perpetual disappointment Taijuan Walker, leaving them short on upside. The Mariners are banking on bounceback seasons from Hisashi Iwakuma and Felix Hernandez, as well as hoping James Paxton can turn that triple-digit fastball into a sub-3.00 ERA.

There are a lot of long shots here, but the Mariners are well positioned to make a run for the AL West crown. We know they'll score runs, and their moves this offseason to remake their identity on the fly might just help them keep enough off the board to steal a weak division.

2017 projected lineup
1
Jarrod Dyson LF
2
Jean Segura SS
3
Robinson Cano 2B
4
Nelson Cruz DH
5
Kyle Seager 3B
6
Mike Zunino C
7
Dan Vogelbach 1B
8
Mitch Haniger RF
9
Leonys Martin CF
Bench
Carlos Ruiz C
Bench
Shawn O'Malley SS
2017 projected pitching staff
1
Felix Hernandez RHP
2
Hisashi Iwakuma RHP
3
James Paxton RHP
4
Yovani Gallardo RHP
5
Drew Smyly LHP
Alt SP
Ariel Miranda LHP
Closer
Edwin Diaz RHP
Setup
Steve Cishek RHP
Relief
Nick Vincent RHP
Relief
Evan Scribner RHP></span> </td> </tr> <tr class=
Relief
Marc Rzepczynski LHP

Was Jean Segura's breakout legit?

We'd seen stretches of strong play from Jean Segura at times in the past. One even propelled him to an All-Star berth in 2013. However, every flash he showed tended to be followed in the past by an extended cold streak, and it seemed going into last year that Segura had settled in as a low-600's OPS kind of bat. Useful in Fantasy as long as he was stealing bases, but hardly someone worth getting excited about.

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His 2016 seemingly changed all of that. Segura put together an absolutely brilliant season, hitting .319, leading the league in hits, while recording career-best numbers in nearly every relevant category. And, unlike in years past, Segura just got better as the season went on, bouncing back from a slow May to post an improved OPS in each of the final four months of the season. The old two-week stretches of dominant play were finally replaced by an entire year's worth of high-round value from Segura. Is this the new normal, or did Segura just never cool off before the season ended?

It would be ridiculous to suggest he was the same guy heading into 2017 as he was in 2015, but there's also some room for Segura to regress. For one thing, playing in Seattle isn't quite the same as playing in Arizona. The lineup isn't much worse, but the hitting environment is, and Segura's power breakout was at least to some extent influenced by such a generous home park. It's not that he was in a hitter's desert when he was in Miller Park, so it would be unfair to say it's all the park, but it might have been a confluence of factors coming together, with Segura improving, having a career year and playing in a beneficial offensive environment.

All of that is to say that Segura may be unlikely to repeat exactly what he did last year for a variety of reasons. But this isn't the same slap-hitting, borderline replacement-level hitter we saw before. Whether you want to bet on a repeat is up to you, but Segura will almost certainly be one of the first seven or eight shortstops off the board in every draft, and for good reason.

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Was 2016 the beginning of the end of King Felix's reign?

Last season was a nightmare for Hernandez by any measure. He posted his worst ERA since 2007, and his 153 1/3 innings of work were his fewest since his abbreviated rookie season. Nearly all of Hernandez's peripherals moved in the wrong direction, to the point that his 4.63 FIP suggests he was lucky to just have his worst ERA in a decade.

Hernandez's decline had already begun in 2015, as his peripherals indicated he was a worse pitcher than his 3.53 ERA showed, so this didn't exactly come out of nowhere. Hernandez is just 30, but with nearly 2,500 innings under his belt, he's a relatively old 30, so it's not crazy to think this is the end.

On the other hand, the Mariners made upgrading their defense a priority this offseason, and it's hard not to feel that was part of Hernandez's regression. On days when Nelson Cruz is the DH -- which should be most days -- the Mariners can run out a starting lineup featuring plus defenders in six or seven of eight spots. If ever Hernandez was going to have a bounceback season, it would be with this defense behind him.

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Can Edwin Diaz be a top-five closer?

As he worked his way up the minor-league ladder, Diaz looked like a decent, but by no means can't-miss pitching prospect. Working primarily as a starter, Diaz struck out 9.5 per nine, with a decent walk rate and a 3.15 ERA, but he often drew criticism for his mechanics and lack of secondary stuff. He wouldn't be the first middling pitching prospect to take that profile and turn it into a long career as an elite reliever, and it certainly looks like he is on that path after one incomplete season in the majors.

Diaz took the majors by storm. His 2.79 ERA won't blow you away, but it also won't tell the whole story, as Diaz was nearly unhittable for long stretches. He had the seventh-best FIP in baseball among relievers, fueled by a ludicrous strikeout rate that put him behind just Andrew Miller, Dellin Betances and Kenley Jansen. That's right, some 22-year-old rookie was a more prodigious strikeout machine than Aroldis Chapman.

That's no guarantee Diaz will thrive in the ninth inning the way his neighbors on the strikeout rate leaderboard do, but with a sinker that lives at 97 and a slider that led all of baseball in swinging strike rate, he's got a chance. Diaz has a chance to be on the short list of best relievers in baseball.

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