The Astros haven’t seen the Mariners since mid-July, so fans have had to watch gleefully from afar as their only mildly threatening division rivals have tumbled down the standings and have basically played themselves out of playoff contention at this point. The last time the two teams played each other, they were battling for first in the division, with Seattle having slipped down from a 10-game lead in mid-June to an eventual tie by the time the Astros left.