The Mariners are bad at pinch hitting, and they do it more than anyone.
The Mariners have called on pinch hitters 118 times this year, the most in MLB. If they keep it up, they’ll set the record for most pinch-hit plate appearances by an American League team since Fangraphs began tracking in 2002. Their 62 wRC+ in those spots suggests the strategy hasn’t really worked.
The logic of the pinch hitter is that the batter coming into the game offers a better matchup than the batter coming out. Teams don’t sub in-and-out players for the sake of giving the manager screen time but because they think it will help them win.