HOUSTON — A simple flip of the ball a few feet — a play they’ve made at a least a 2,000 times since the start of spring training — might have been the difference from a win to a loss.

And not making that play Tuesday night severely damaged the Mariners’ wild-card hopes.

Shortstop Ketel Marte’s errant throw on what would have been an inning-ending double play touched off a tire-fire of a sixth inning that saw the Astros score six runs and turn Seattle’s 4-2 lead into an eventual 8-4 defeat.

The Mariners fell to 83-74, and it was the fourth time this season Seattle has lost its next game after reaching 10 games above .500. With Baltimore losing, the Mariners could have moved within a game of the second wild-card spot. Instead, they remain two games back with five games to play.

The Mariners have dealt with some bad innings featuring regrettable defense this season, but what transpired in the sixth inning was a reminder of the season-long warts the team has had overcome to be in contention for a postseason spot.

Tuesday’s issues began with two mistakes by Marte on one play. With one out and starter Felix Hernandez trying to work around back-to-back singles from Jose Altuve and Carlos Correa, Houston’s Yuli Gurriel hit a ground ball up the middle that Marte fielded about 10 feet from the second-base bag.

Robinson Cano — a multiple Gold Glove-winning second baseman with a rocket arm — was standing near the base waiting for Marte to flip him the ball and fire to first. Instead, Marte opted to run to second base to get the first out, then threw off balance to first.

The throw was several feet right of first baseman Adam Lind. Not only did the Mariners not get the double play to end the inning, but Altuve wisely kept running and scored on the play to cut the lead to 4-3.

Marte’s two errors — one mental and one physical — led to a run and kept the inning going, an inning that didn’t end until five more runs scored and six more hitters came to the plate.

Hernandez played a role in the avalanche, inexplicably walking the light-hitting Tony Kemp. It also moved Gurriel — the tying run — into scoring position. That loomed large when pinch-hitter Alex Bregman was able to flare a 1-2 curveball into left-center to plate the tying run.

Even with all that went wrong, the Mariners should have exited the sixth with the scored tied 4-4. Hernandez got the next batter, Jake Marisnick to hit a check-swing ground ball to first base. But the routine out never came. Lind misplayed the ball, picked it up and headed for the bag while looking to flip the ball to a covering Hernandez.

But Hernandez was slow to the base, so Lind was forced to hustle and tag the base, but Marisnick’s head-first dive into first beat Lind by inches. The Mariners asked for a replay but the call was upheld.

Again, the inning continued.

From there, Hernandez fell apart. George Springer hit a ground-rule double over the wall in right to score two runs for a 6-4 lead. Marwin Gonzalez followed with a two-run single to center to end Hernandez’s night.

Reliever Drew Storen got the final out, but too much damage had been done.

The Mariners grabbed 1-0 lead with two outs in the top of the first against Astros starter Mike Fiers. Robinson Cano blooped a double into the left-field corner and scored moments later on Nelson Cruz’s sharp single to center.

The Astros answered in the bottom of the first against Hernandez. With one out and leadoff hitter Springer on first, Altuve launched a double off the wall in left-center to tie the game. He scored a batter later when Correa singled into right field to make it 2-1.

But unlike their previous outing against Fiers where they mustered just one run in six innings, the Mariners rallied with two runs in the top of the second on a Nori Aoki RBI double over the head of Springer in right field and a sacrifice fly from Seth Smith that made it 3-2.

Seattle pushed the lead to 4-2 in the third inning. With Cruz on first base, Lind hit a two-out line-drive double that rolled up Tal’s Hill in center field. Running on contact, Cruz never stopped running, scoring on the play when the throw in from the outfield was mishandled by catcher Jason Castro at the plate.