HOUSTON -- Jason Heyward hit a go-ahead, two-run homer and made a dazzling defensive play as the Houston Astros beat the Seattle Mariners 4-3 on Tuesday night to clinch their fourth consecutive American League West championship.

Alex Bregman and Kyle Tucker each added a solo home run for the Astros, who are headed to the postseason for the eighth year in a row.

The Astros trailed by one with no outs in the fifth inning when Victor Caratini singled before moving to second on a sacrifice bunt by Jeremy Peña.

Heyward, who wowed on defense in the top of the inning, launched his home run to the second deck in right field off Logan Gilbert (8-12) to put Houston on top 4-3.

Heyward, who signed with the Astros last month after his release by the Dodgers, is filling in for Yordan Alvarez, who is out because of a knee sprain.

The Mariners had runners on first and third with one out in the eighth before Ryan Pressly retired Mitch Garver on a fly ball. Josh Hader took over and struck out J.P. Crawford to preserve the lead.

Hader returned for the ninth and retired pinch hitter Luis Urias before striking out Victor Robles and Julio Rodríguez to earn his 34th save.

Framber Valdez (15-7) permitted eight hits and three runs in 5 innings for the win.

Jorge Polanco homered among his season-high four hits and had two RBIs for the Mariners, who dropped 2 games behind in a crowded race for the final AL wild-card spot that also includes Detroit, Kansas City and Minnesota.

Justin Turner and Polanco singled to open the sixth, but Garver grounded out before Valdez struck out Crawford to end his outing.

Bryan Abreu came in and pinch hitter Luke Raley grounded out as Houston escaped the jam.

Gilbert gave up five hits, four runs and tied a season high by giving up three homers in six innings.

There were two outs in the first when Bregman sent a fastball from Gilbert over the fence in center field to make it 1-0.

Polanco tied it when he homered to left on Valdez's second pitch of the second inning.

Rodríguez and Cal Raleigh singled to open the third before the Mariners took a 2-1 lead on an RBI double by Randy Arozarena. There was one out when Polanco singled to score Rodríguez and make it 3-1.

Tucker's shot to start the Houston fourth sailed over the short wall in right field to cut the lead to 3-2.

Heyward robbed Raleigh of extra bases with a leaping catch in left field for the second out of the fifth. Heyward crashed into the metal scoreboard on the wall after making the play, knocking out a panel with his left hand.

He was shaken up by the collision and fell to the ground writhing in pain. Heyward was checked by an athletic trainer but remained in the game before hitting his homer in the bottom half.

The Associated Press contributed to this report.