Luis Castillo, Emerson Hancock among Mariners’ trade candidates

This story was excerpted from Daniel Kramer’s Mariners Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

ARLINGTON — For all their struggles in what’s been one of their toughest stretches of this era, the Mariners do still have a Trade Deadline to work with.

And it’s right around the corner, one week from Monday.

The Deadline has…