At the time of Eugenio Suárez's grand slam in the bottom of the eighth during Game 5 of the AL Championship Series versus the Blue Jays, it was the biggest hit in Mariners franchise history. However, aside from ultimately being irrelevant (in a manner of speaking), it was also one of few memorable moments from his second tenure in Seattle.
This is not to imply the Mariners were wrong to bring Suárez back at the July 31 trade deadline, as some might claim with that wonderful benefit of hindsight. He was having a tremendous season in Arizona and was the type of clubhouse leader the Mariners needed, as ownership went all-in on improving the roster for their assault on a first World Series berth.