The Seattle Mariners offense is struggling. Despite the offseason addition of Nelson Cruz and the presence of Robinson Cano and Kyle Seager, the M’s offense is in a rut. Entering the week, only the White Sox and Phillies had scored fewer runs.

Given all these factors, the addition of Mark Trumbo would seem like the best early Christmas present known to man. Yeah… not so much.

Trumbo’s early impact, or lack thereof, has been staggering considering the slugger’s track record.

The former Angel was a massive hit for his hometown team, averaging 32 home runs, 94 RBI and a .251 average over three full seasons with the Halos. The M’s needed that Trumbo, not the one they acquired. The first baseman/corner outfielder/designated hitter (he basically plays every “power” position on the diamond) had a rough go of things in Arizona. With the Diamondbacks he tallied 23 bombs, 84 RBI and 128 strikeouts in 134 games. Those aren’t that awful numbers, but when you consider the stats were accumulated over the course of two seasons, it encourages pause.

The Mariners certainly gave up some quality pieces to bring a player who once finished second in Rookie of the Year voting and appeared in an All Star game during his first two seasons.

Out went Welington Castro, Dominic Leone and minor league prospects Gabriel Guerrero and Jack Reinheimer.

(It should be noted that reliever/swing man Vidal Nuno made the move north with Trumbo in the transaction, so the M’s upgraded their bullpen to some extent).

Losing Castillo is the most prominent negative here. Yes, Leone had his moments last season in relief, but he struggled this year and Nuno is likely an upgrade over the now-former Mariner.

Seattle’s catching situation is pretty straight forward. Mike Zunino is the starter and Jesus Sucre is the backup. However, Zunino is hitting .158 with a .230 OBP while Sucre is scuffling with the bat. His batting average, OBP and slugging percentage are all .043. He owns the rare distinction having an OPS under .100. Yes, that’s right, Jesus Sucre’s OPS is .087. Yikes.

So why is this being mentioned? Because Welington Castro happens to be a career .251 hitter, who at his best hits somewhere in the .260-.270 neighborhood.

Why he was dealt for a struggling Trumbo is puzzling.

Trumbo put up half-way decent numbers (9 home runs, 23 RBI, .805 OPS) in 46 games in the desert prior to the trade—however, Seattle was already well-stocked in the first-baseman/corner outfielder/designated hitter areas. In fact, they had a log jam on their hands. Logan Morrison was/is entrenched at first base, while the pre-Trumbo corner outfield/DH candidates included Nelson Cruz, Seth Smith, Justin Ruggiano and Dustin Ackley. James Jones has also received at-bats in the outfield.

Adding Trumbo to this mix makes sense if the Trumbo in question is the one who suited up for the Angels. However, sacrificing an above-average offensive catcher (Castillo) and two prospects for the Trumbo who suited up for the D-Backs is, in layman’s terms, a bad deal.

Losing Castillo hurts catcher production, while adding Trumbo to a position where there is a surplus only rubs salt in the wound. While Zunino is clearly the starting catcher, he’s struggling with the bat, as is his cover, Sucre. Sacrificing offensively behind the dish is fine trade-off when you acquire pre-Diamondback Mark Trumbo, but sacrificing behind the dish for a player who hit entered the week hitting .179 as a Mariner… well, then you have some problems.

The Mark Trumbo acquisition will be a win for the Mariners if the slugger can regain the form he displayed with the Angels, however if he continues his downward trajectory, the M’s may soon come to regret the trade.

All stats courtesy of Baseball-Reference.com unless otherwise noted.