Chicago Cubs trade Welington Castillo to the Mariners

Good morning! The Mariners have made a trade.

Source: Cubs have traded catcher Welington Castillo to Seattle.

— Jeff Passan (@JeffPassan) May 19, 2015

It's the first real challenge to Mike Zunino's job since his promotion. Castillo had spent most of 2015 as the 3rd catcher on the Cubs, sharing time with David Ross as the backups to Miguel Montero, who is currently crushing with a 149 wRC+.

There's no indication of who's departing in return, at least not yet. The cost shouldn't be significant, as the Cubs have been operating under very little leverage for a while now, since everyone in the league knew they were shopping Castillo for the better part of the last five months.

Castillo is currently sporting a 0.0 WAR and 51 wRC+ through 47 games, but had a 5.5 WAR combined over the previous two seasons. While the offense declined last year, Castillo's wRC+ of 91 still topped the 86 Mike Zunino contributed. The previous two years, Castillo had wRC+ of 102 and 107. He might not be a big offensive upgrade today, but the bar has been set pretty low.

With Zunino's strikeouts on the rise and overall offense production on the decline, there's a solid chance Castillo is coming over to play a lot, not just replace Jesus Sucre. Maybe the Mariners feel inclined to ship Zunino back to AAA, which wouldn't be the worst idea -- there's a clear path to playing time, and outside of the occasional burst of massive power, Zunino is putting together a miserable offensive campaign with obvious issues to work on.

Here's the bad news -- while Castillo has thrown out a slightly-above-average 30% of would-be base stealers, he's rated among the game's worst pitch framers, something Zunino excels at. The difference is staggering -- while Zunino grabbed an extra 168 strikes last year, Castillo coughed up 183 extra balls. That's a drop from second best in baseball to second worst, a mammoth difference of 351 pitches that will probably fly under the radar by many as this is evaluated. It depends on what version of Castillo appears at the plate, but when defense and offense are combined, this is much closer to a wash, and if Castillo's decline at the plate is real, it might be worse.

That being said, it's hard to evaluate, as a trade. We don't know the cost, we don't know if Castillo is replacing Zunino or if he's merely unseating Sucre to light a fire under Zunino and give them a viable MLB catcher if the M's do decide to ship Zunino back to Tacoma. I'm all about acquiring talent, but a one for one swap of Castillo and Zunino probably isn't going to help the Mariners, especially when you look beyond the slash lines. That being said, it's likely the M's were able to buy low here and organizational depth is never a bad thing, especially since Castillo is controlled for three seasons (including 2015), and is a talented player at a difficult position to fill.

Castillo is 28 and is making $2.1 million this year in his first year of arbitration. We'll update this post as we learn the cost to acquire his services.

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Update: The cost is Yoervis Medina, straight up. From talent exchanged, it seems like a perfectly fair swap, with the Mariners receiving far more upside than the Cubs on positional scarcity alone. Medina's velocity has been down this year, and he hasn't missed nearly as many bats as he did the previous two seasons.