Compare the numbers over the past three years for Gary Sanchez in his age 25, 26 and 27 seasons (2018-20) and the numbers for catcher Mike Zunino in his age 25, 26 and 27 seasons (2016-18):
GS 244 G, 998 PA, 132 R, 62 HR, 154 RBI, .200/.296/.453/.748, OPS+ 99, 3.7 bWAR, 4.0 fWAR
MZ 292 G, 1032 PA, 105 R, 57 HR, 139 RBI, .223/.300/.462/.763, OPS+ 107, 7.0 bWAR, 8.3 fWAR
Following the 2018 season Seattle traded Zunino, Michael Plassmeyer and Guillermo Heredia to Tampa Bay for Mallex Smith and Jake Fraley. Sanchez likely has far less trade value because of his defensive deficiencies.
Or not.