Will The 2015 Seattle Mariners Be Undone By Defense?


Don’t look now, but the Seattle Mariners have just about shored up all the holes that plagued their offense in 2014. There’s almost no chance we’ll see Stefen Romero patrolling the outfield, and Corey Hart is one Pittsburgh away from turning DH into a black hole. Nelson Cruz, Justin Ruggiano, and Seth Smith are all good hitters, and they give the team a big boost on offense.

More from Seattle Mariners

But there’s more to baseball than scoring runs. You’ve got to prevent runs, too, and that’s something the Mariners were pretty good at last year. With a strong rotation and a dominant bullpen, the M’s have half of their run prevention unit covered. But it’s the other half of keeping the opponent off the board that’s becoming a worry again: the position players.

Defense used to be huge for the Mariners. The 2009 team had the best defense in the major leagues, and cruised to a feel-good winning season on the strength of the outs they’d create in the field. When the 2010 team stunk the front office changed their philosophy, and ended up having crappy defenses until virtually chancing their way into a strong fielding 2014 team.

Now the Mariners are entering the season as a World Series contender, having retained all the non-Brandon Maurer arms that made them awesome in 2014 and improving their short-sticked offense. But team defense has crept back into focus, and not because the team stocked up on gold glovers. Yeah, the M’s might be pretty bad in the field in 2014.

On the surface this seems like an overreaction, probably. Michael Saunders plays an awesome right field, which can’t be said of Smith or Ruggiano. So the Mariners were able to keep most (all?) of the offense they traded away to Toronto, but at the cost of defense. So they’re worse at one spot. But it’s more than that.

Dustin Ackley is your starting left fielder, and he made big gains in the field last year. At least, that is, according to some metrics. He’s still young, and is athletic enough that he could be reasonably expected to sustain his improvements in the field. But that’s absolutely not true as far as his throwing arm is concerned. He can’t throw, is what I’m getting at. You want an outfielder to be able to throw the ball to the infielder, and even in left, Ackley can hardly do that. So there’s a big, scary chance of regression there.

Austin Jackson is an above-average center fielder for his career, but the downward trend over the last two seasons has been stark and scary. He was slightly below average in 2013 before falling to -6.3 DEF, according to FanGraphs. Defense peaks early, and so Jackson simply can’t be counted on to provide value in center. And center’s a pretty important spot.

So the outfield’s a potential mess. What about the infield? Logan Morrison sucks at defense, just like most first basemen. Robinson Cano passes the eye test, but metrics find him to be roughly average. Shortstop is covered, as both Brad Miller and Chris Taylor are excellent defenders. Mike Zunino is an elite defensive catcher.

Which leaves one guy. Kyle Seager turned in a season that was rightly rewarded with a Gold Glove. He’s a $100 million man, thanks in no small part to his suddenly-elite defense at third. But that’s the thing: Seager’s rise was so huge and so sudden that we can’t just write off the possibility that it was a one-year blip. Or, at least, that 2014 represented his defensive peak. There’s a good chance that never happens again.

Seager’s average at the very worst, so it’s not like he could sink the M’s defense or anything. But Cano’s aging, Jackson’s aging, Ackley’s got a big handicap he’ll likely never overcome, the right field platoon is bat-only, LoMo is a first baseman, and the M’s are trying to win a lot of games. This could end well, but it could also be the team’s undoing.

The 2015 Mariners are unlikely to be defined by their defense. They’ve got good gloves at several important positions, and don’t have any Michael Morse-types wandering around out there. But if nothing it’s a concern, and something worth keeping an eye on. But on the othe hand, Kyle Seager just won a Gold Glove. They should be alright.