Just one year ago, the Seattle Mariners propelled themselves into wild card contention with a torrid 18-9 win-loss record in September. The club fell short of a playoff berth, but their strong finish energized baseball fans throughout the Pacific Northwest.

The combination of that late season surge and the aggressive offseason maneuvering of general manager Jerry Dipoto further fueled optimism for 2017. Perhaps, this would be the year the Mariners returned to the postseason for the first time since 2001.

Then, reality set in.

The Mariners regressed finishing 78-84 and a distant third place behind the division champion Houston Astros.

There were good news stories about individual players having breakout years. But, the club finished with a losing record. Worse yet, they missed the postseason for the sixteenth consecutive year.

Now, Dipoto and his staff face a difficult challenge.

Add the necessary pieces to end that dreaded postseason drought without forfeiting progress made during their first two years running the team.

Certainly, entering another offseason without a playoff appearance — or even a winning record — is frustrating for Mariners fans. But, the team’s struggles do provide great story material for Prospect Insider.

In the coming weeks and months, we’ll provide analysis on Seattle’s 2017 season, hot stove items, prospects, player development, and much more from around the league.

Today, let’s talk about the Mariners’ offense and potential areas to improve before Opening Day.

By The Numbers

For starters, I thought I’d perform a side-by-side comparison of the Mariners’ offensive output during this season and 2016. Please note; the team’s AL ranking is in parenthesis.

Mariners Offense Rankings (AL)
2016 4.74 (3) 223 (2) .259 (7) .326 (5) .430 (6)
2017 4.63 (7) 200 (10) .259 (6) .325 (6) .424 (9)

Overall, the numbers are very similar. Batting average and on-base percentage (OBP) are virtually the same.

Home runs were down, but that’s not surprising. No one expected newcomers Ben Gamel, Danny Valencia, Guillermo Heredia, Jarrod Dyson, and Mitch Haniger to collectively match their predecessors in the power department.

Still, the most important statistic declined in both quantity and standing in the league — runs scored/game (RS/G).

Some of you may suggest the Mariners’ run production didn’t slip that much. Scoring .11 runs less-per-game isn’t exactly falling off a cliff.

True, Seattle’s offense didn’t tank. But, that minor dip in production combined with other clubs improving left the Mariners slightly below league-average after being top-3 in runs scored the previous year.

Beyond the slight drop in scoring, there’s another aspect of the offense worth noting — its uneven nature.

Seattle’s offense proved to be potent scoring 6-plus runs 62 times this season. Only the Astros (72), New York Yankees (65), and Texas Rangers (62) matched or exceeded that mark.

Despite the high number of dynamic performances, the Mariners’ lineup was held in check at a high rate too. The Kansas City Royals (33) and Toronto Blue Jays (32) were the only team to plate one-or-fewer runs more often than Dipoto’s club did (30).

Why The Volatility?

Two factors driving the Mariners’ inconsistent run production were injuries and ineffectiveness.

Several key contributors were lost to the DL, some more than once. In nearly every instance, replacements didn’t have the hit tool to replace a starter — many don’t.

In other cases, substitutes were thrust into situations exposing weaknesses. For instance, a right-handed hitter who struggles against righties taking on an everyday role.

Positional Review

To help illustrate how Mariner hitters performed, I’ve broken down the lineup by position. My metric of choice for this assessment is wRC+.

For those not familiar with wRC+, it permits comparisons of hitters from different years, leagues, and parks. League-average is always 100.

For example, Nelson Cruz had a 146 wRC+ this season. That means he created 46-percent more runs than the league-average player. That sounds about right, doesn’t it?

Please note I highlighted positions that were at least league-average wRC+. By doing so, it becomes readily apparent where the lineup flourished or struggled.

2017 Mariners Run Creation
Pos wRC+
C 108
1B 92
2B 101
SS 90
3B 105
RF 103
CF 75
LF 89
DH 140

Source: FanGraphs

Now that we’ve identified the rough spots on the roster, let’s turn our attention to each position individually. This should provide insight into where Dipoto is most likely to seek improvements.


The season got off to a bumpy start for Opening Day receiver Mike Zunino. After posting a .486 OPS through early May, he found himself playing for Class-AAA Tacoma.

Zunino returned to Seattle just three weeks later with adjusted swing mechanics and outstanding production. The 26-year-old slashed .266/.348/.563 and hit 25 home runs for the remainder of the season; all were career highs.

Unless Dipoto opts to flip Zunino in a trade, the club has their catcher going into next season and perhaps beyond. Whether the former Florida Gator produces a similar stat line in 2018 is debatable.

Having said that, Zunino can regress some and still provide value. If the five-year major leaguer posts numbers similar to his combined 2016-17 slash (.238/.327/.497), the Mariners have a potential all-star on their hands.

Wouldn’t that be something?

Carlos Ruiz proved to be a solid backup to Zunino. But, the 38-year-old is a free agent and it’s unclear if he’ll return.

If Ruiz departs, management will need to determine whether to invest in another veteran or rely on a less experienced, younger, and cheaper backup catcher. The club’s approach may shed light on management’s confidence in Zunino going forward.

First Base

When the Mariners determined in Spring Training prospect Daniel Vogelbach wasn’t ready to help the big league club, projected platoon-mate Danny Valencia became the everyday first baseman.

Valencia struggled mightily during April, but he bounced back to have a strong first half. From May 2 until the all-star break, the right-handed hitter slashed .303/.361/.457 and slugged eight home runs.

During his hot streak, Valencia excelled regardless of pitcher handedness. In the second half though, his success against righties quickly evaporated.

With Valencia struggling against like-handed pitching, Dipoto traded prospect Boog Powell for left-hand hitting rental player Yonder Alonso in early August.

Alonso provided solid production platooning with Valencia. As a Mariner, the left-handed hitter posted a .277/.372/.445 slash and 126 wRC+ in 137 plate appearances against righties.

With both Valencia and Alonso set to test free agency, Dipoto will be looking for a player — or players — to play first base.

Perhaps, Seattle gives Vogelbach another shot next year. But, they’ve had opportunities to do so this season and didn’t.

The Mariners pursuing Alonso is plausible. His .277/.349/.422 slash and 113 wRC+ in over 2,200 plate appearances against right-handers suggests he’d be a good complementary piece to the heart of the lineup.

If the Mariners managed to agree to contract terms with Alonso, they’d likely pursue a right-handed hitter capable of playing first base. A utility player capable of playing multiple positions would be preferable.

Second Base

After having his best season as a Mariner last year, Robinson Cano produced a slash line reminiscent to his disappointing 2015 production. That’s the year he played through a double sports hernia for at least two months.

Perhaps, his sub-par season was again injury-related; hamstring and quad issues dogged Cano for over two months. Maybe, it’s a simply a sign of age-related regression.

Assuming good health, I suspect Cano bounces back next year. Sure, there may be a slight decline in production attributable to age. But, he’s too talented and dedicated to his craft to go into a dramatic tailspin.

Two years ago, I suggested the Mariners consider moving Cano to first base. I still believe it’d be wise to consider the notion.

With the eight-time all-star signed through his age-40 season, it’s unlikely he finishes his career at second base. Moving him now would solve the club’s current first base problem.


Leg issues also plagued Jean Segura, who landed on the DL twice. Despite his injury woes, the 27-year-old put together a good first season with Seattle — .300/.349/.427 and 111 wRC+.

In fact, the Mariners were so pleased with their new acquisition they signed him to a five-year/$70 million extension in June.

Considering his age and the fact he averaged 147 games during the four seasons before 2017, Segura’s durability isn’t an issue. However, adding a more capable utility-man to spot their star shortstop — and other infielders — would be beneficial.

During Segura’s first absence in April, utility-man Taylor Motter exceeded expectations with a .988 OPS and 5 home runs. Unfortunately, the 28-year-old’s production tailed off afterwards.

When Segura was lost for 18 games in June, Motter produced a meager .182/.220/.255 slash and just two extra-base hits in 59 plate appearances.

If the Mariners were to adopt my hair-brained idea of moving Cano, sliding Segura to second base could be an option. Such a move would have the ripple effect of causing an opening at shortstop and organization club doesn’t have an internal option ready to fill the position.

Third Base

After a career-year in 2016, expectations were high for Kyle Seager. Unfortunately, his 106 wRC+ this season was his lowest since becoming a regular in 2012. His slash line was similarly down too.

I know a segment of fans is never going to be pleased with Seager. My guess their angst is partially rooted in the fact he’s set to make $19 million next season. They expect all-star production for that much money.

Fair enough, but the Mariners would be selling low by trading Seager now. Look at the facts; the seven-year veteran is coming off a down season, he turns age-30 in November, and his salary is about to jump significantly.

Besides, there’s no heir apparent waiting in the wings. Moving Seager would create another hole requiring exterior resources to fill.

A more likely scenario is Seager holds down the hot corner next season and until his contract expires in 2021. Unless there’s an underlying health issue, it’s reasonable to expect the former third round pick bounces back to his career norms next year.

Right Field

Of all the 10 rookie hitters used by Seattle this season, Haniger was easily the best. Based on the Baseball Reference version of wins above replacement (bWAR), he was the fourth most valuable rookie position player in the majors despite two stints on the DL.

Considering the randomness of his injuries — strained oblique, smashed finger during a bunt, hit in the face with a pitch — there’s no reason to believe Haniger has significant durability issues. With that in mind, he’s on track to be the Opening Day right fielder for the 2018 Mariners.

Center Field

When Leonys Martin went to the minors in late-April, Dyson became the primary center fielder. While the 33-year-old scuffled early, his final stat line were in line with career norms.

The left-handed hitting Dyson primarily faced opposite-handed pitching. When he did face lefties, the results weren’t positive; a 9 wRC+ in 67 plate appearances.

The clubs’ other center fielder was Guillermo Heredia. The 26-year-old played over 460 innings in both center and left field this season.

The right-handed hitting Heredia performed best when facing southpaws (118 wRC+) rather than righties (61 wRC+). This suggests he may be best suited to serve as a platoon or fourth outfielder.

It’s worth noting the Mariners announced last week Heredia was suffering from a partial shoulder dislocation throughout the season. He’ll be undergoing corrective surgery during the offseason.

Perhaps, the shoulder caused Heredia’s late season slump — .204/.274/.268 slash and 47wRC+ in his last 45 games. However, his struggles may also be attributable to facing more right-handers when Dyson was lost to the DL in August and September.

Without doubt, Dipoto addresses center field in the offseason. Dyson is a pending free agent and Heredia doesn’t appear to be an everyday solution. Moreover, his injury may affect his Opening Day availability.

Depending on his contract demands, retaining Dyson may make sense. Still, there’s a risk with resigning the Mississippi native. He’ll be 34 next August and has never played 120-plus games in his career.

An alternative approach could be finding a younger, cheaper version of Dyson to pair with Heredia. On the other hand, the team may seek to acquire a full-time player.

I’ve read suggestions Haniger could move to center field. That’s a possibility, but that opens a hole in right field with no readily available replacement.

Bottom line, the Mariners will need to add another outfielder from outside the organization, if Dyson leaves.

Left Field

The other rookie outfielder positively affecting the offense was Gamel. The left-handed hitter became a regular in late-April and did not disappoint.

Gamel slashed .275/.322/.413 and hit 11 home runs — most in his professional career. Also encouraging was his respectable performance (.275/.299/.400) against left-handed pitching.

Having said that, Gamel’s productivity declined during the second half of the season. The 25-year-old’s post all-star game OBP was .262 after being as high as .414 in late-June.

Perhaps, the league adjusted to Gamel or the first year player simply regressed to the mean as the season elapsed.

Considering his good debut season, age, and the fact he’s under team control for five more seasons, sticking with Gamel in left field makes sense. Especially with more pressing needs in center field and first base.

Designated Hitter

Clearly, Cruz was the best and most consistent hitter on the roster. Despite playing through knee and calf injuries at different points of the season, the 37-year-old led the team in games played, home runs, OPS, and wRC+.

Next season will be the last of Cruz’s four-year/$57 million deal. Unless Dipoto opts to blow up his roster, the Mariners have their designated hitter for 2018.

It’s possible Cruz suffers significant age regression. But, it hasn’t happened yet despite dire warnings from many observers — including me.

Barring injury, a more likely scenario is Nelson Cruz continues to perform at a high level next year.


As the hot stove starts warms for Seattle baseball fans, there are clear areas of need with the offense. Most critically, first base and center field.

Based on his first two years in the Emerald City, Dipoto will be busy upgrading those spots and other areas on his roster as soon at the World Series concludes.

Prospect Insider is looking forward to the action.

Got a take on what you just read? Talk about it here!

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Luke Arkins

Luke is a native New Yorker, who grew up as a Mets fan. After the US Navy moved him to the Pacific Northwest in 2009, he decided to make Seattle his home. In 2014, Luke joined the Prospect Insider team. During baseball season, he can often be found observing the local team at T-Mobile Park. You can follow Luke on Twitter @luke_arkins

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