SEATTLE -- The Astros still control their own destiny in their attempt to reach the playoffs for the seventh consecutive year, but the defending World Series champions have very little room for error in their final four games of the regular season.

Tuesday night at T-Mobile Park was probably one of Houston’s sloppiest games of the season, which is a disheartening development, considering the stakes. Their 6-2 loss to the Mariners has them barely clinging to the final Wild Card spot in the American League -- and sets up a pivotal series finale on Wednesday.

With the win, the Mariners pulled even with the Astros in the loss column and are one-half game behind them in the standings ahead of the series finale, which will determine which team will have possession of the final Wild Card spot in the American League entering the final series of the regular season.

• Games remaining (4): at SEA (1), at AZ (3)
• Standings update: The Astros (86-72) are in second place in the American League West, 2 1/2 games behind the Rangers (88-69). Seattle (85-72) is one-half game behind Houston for the third and final AL Wild Card spot. The Astros hold the season tiebreaker against the Rangers, but not the Mariners.

“Probably the biggest game of the year,” Astros second baseman Jose Altuve said of Wednesday's finale. “Gotta win. Gotta go out there and score more runs than them and win the game, win the series.”

The Astros, who have lost 10 of their last 14 games and dropped to 9-14 in September, committed three errors and went 2-for-13 with runners in scoring position. They scored one total run after having bases-loaded opportunities with less than two outs in the first and seventh innings.

Mariners starter George Kirby wriggled his way out of a bases-loaded jam in the first inning and settled down to throw six scoreless innings. With the bases loaded and no outs in the seventh, Houston managed only a sacrifice fly from pinch-hitter Jon Singleton.

“We had him on the ropes in the first inning and then we had another bases loaded and nobody out, and we just got one run out of it,” Astros manager Dusty Baker said. “We didn’t play real well tonight. We kind of threw the ball around and then we didn’t back up the bases a couple of times. We didn’t play well.”

Astros starter Cristian Javier, coming off a promising 11-strikeout performance Wednesday against Baltimore, lasted only 4 2/3 innings, giving up four runs (three earned) on three hits and three walks, one of which scored. 

“He threw the ball well tonight,” Baker said. “We just didn’t help him.”

Altuve and right fielder Kyle Tucker committed errors on throws to third base and Bregman made a fielding error at third base, though the runner didn’t score. On both throwing errors, Astros pitchers didn’t back up the base either time -- Javier in the third and Rafael Montero in the fifth.

“I think you’ve got to flush it and move on to tomorrow,” Bregman said. “We’re a very good defensive ballclub. We need to play good defense [in] the next four games.”

Even when the Astros did square up the ball, it just wasn’t their night. Bregman hit a long fly ball to right field in the sixth inning and was robbed of extra bases on a great catch at the wall by right fielder Teoscar Hernández.

“Pretty stunned,” Bregman said. “I thought it had a chance of leaving the yard. He jumped up and caught it. Part of the game. He made a hell of a play. I thought I put a good swing on it.”

Altuve’s error in the third helped the Mariners push across the first run of the game and forced the Astros to play from behind, which has been a common theme in September. Altuve took a relay throw from Tucker --  who had speared a line drive off the bat of Josh Rojas in deep right field -- and tried to throw out Mike Ford, who was attempting to advance from second to third. Altuve's throw sailed into a photo well and Ford came home. Ty France, on base with a previous single, wound up at third, where he'd score two batters later.

“I’ve got to hold the ball there and try to give the pitcher the opportunity to play for a double play,” Altuve said. “I put the team in a tough situation with that terrible throw.”

And with that, the Astros will come to the ballpark Wednesday with their season on the line.

“We want to play good and we want to make no errors and hit, but these kind of games are going to happen,” Altuve said. “The key is just to leave it behind you and forget about it and show up and be the best player you can be and help your team to win.”