As others on this forum have noted, Baseball Trade Values likely undervalues Luis Castillo.
The comparison is three years of a 31-year-old established starting pitcher and three years of a 31-year-old position player who should be limited to designated hitter duties.
So far this year Luis Castillo has posted 2.4 fWAR after posting 3.3 fWAR last year. So far this year Masataka Yoshida has posted 1.0 fWAR after posting 0.6 fWAR last year.
Before this season the ZiPS three-year projections had Castillo with 3.9, 3.4 and 2.9 WAR and Yoshida with 2.1,, 1.7 and 1.3.
Bloated contract aside, Seattle would probable prefer to fill the DH slot with Mitch Garver, with a career OPS+ of 116, including 111 over the past two seasons, over Yoshida, with an OPS+ of 113 over his two MLB seasons. After his horrendous start this year Garver has shown signs of life in limited September action.