The first triple play of the 2018 season was a weird one.

Thursday afternoon at Safeco Field (GameTracker), Houston Astros DH Evan Gattis banged into a 5-4-3 triple play that was anything but routine. With runners on first and second, Gattis hit a grounder to Seattle Mariners third baseman Kyle Seager, who stepped on third for the first out and fired to second for the second out.

That's when it got weird. Gattis, who was safe at first after Robinson Cano elected not to make the throw, apparently thought the inning was over. He started to head back to the dugout and the Mariners tagged him out in the middle of the infield. Check it out:

That is definitely a new one for me. I've seen plenty of runners (and hitters and defenders) forget how many outs there are in the inning. But forgetting the outs and becoming the final out of a triple play? Yeah, haven't seen that before. Gattis' teammates are going to get on him about that.

The triple play is the first for the Mariners since 2015, when they turned a 3-6-2-2 triple play against the Toronto Blue Jays. The Astros last hit into a triple play in 2016. George Springer did the honors with a traditional 5-4-3 triple play against the Chicago White Sox.