The Mark Trumbo trade will not fix Mariners' offensive woes

Yesterday, the Mariners acquired outfielder Mark Trumbo in a six-player deal with the Diamondbacks, marking the first notable trade of this year's Trade Deadline season. 

The Mariners offense is bad. They have scored the third-fewest runs in baseball, below really bad teams in the Milwaukee Brewers and the Cincinnati Reds. 

Yet, the Mariners still find themselves not quite out of it. They're only five games below .500 and only 3.5 games out of the second Wild Card. With just some life out of their offense, the Mariners could be much better. 

Mark Trumbo could be that life. He hits for a lot of power and could drive in a lot of runs for a team that needs a lot of runs to be driven in. 

I'm a saber-savvy person. And being saber-savvy means that RBI mean nothing, or almost nothing. 

Trumbo has had issues getting on base throughout his career, as his career .298 OBP ranks 38th-worst among 353 qualified hitters in baseball since he came into the big leagues in 2010. 

When Trumbo is not hitting home runs, he is not getting on base either. Despite a high .464 career slugging percentage and an even better .506 mark this season, Trumbo is barely better than average at creating runs on offense. 

Trumbo's wRC+ (weighted runs created plus) is 115 this year, suggesting that he has created 15 percent more runs as compared to the league-average player, adjusting to park effects. 

I'm expecting that number to go down. The only reason Trumbo's wRC+ is that high is due to his power. But Safeco Field, where the Mariners play, is an extreme pitcher's park. 

So, basically what I'm saying is that Trumbo's home run rate is bound to go down. And since he cannot get on base, likely due to being a free-swinger, Trumbo's overall offensive value is going to go down. How much? I don't know. 

What I do know, however, is that Trumbo will likely be replacing Logan Morrison at first base. Morrison, whose career slugging percentage is over 20 points below Trumbo's, has the same career wRC+, likely due to his higher walk rate and better OBP. This season, his wRC+ is a mere 15 points behind. But that could improve due to a low batting average on balls in play.

If you could fuse Logan Morrison and Mark Trumbo together, you would get the ideal player for the Mariners situation. But you can't. Morrison has the on-base abilities and Trumbo has the power. In Safeco Field, however, you need both to be productive. 

The Mariners front office likely made this move in desperation of a flailing offense. The Mariners lost five games in a row and were just swept by the New York Yankees. 

But digging deeper, Mark Trumbo will not fix the Mariners offense. 

--Devan Fink

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