On January 23, 2018, first baseman Jon Singleton and pitcher Dean Deetz were suspended after testing positive for substances violating MLB's drug policy. Singleton, a former Astros' number-one prospect, had tested positive for the third time and was banned for 100 games.
Roster moves
November 2, 2017: The following players became free agents at the conclusion of the World Series:
* Luke Gregerson : Signed two-year, $11 million contract with the St. Louis Cardinals, with a vesting option for the 2020 season, on December 13, 2017.
December 13: Signed free agent right-handed relief pitcher Joe Smith to a two-year contract worth $14 million.
Arbitration-eligible players
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Trades
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Regular season
was the Opening Day starting pitcher for Houston at Globe Life Park in Arlington, versus Cole Hamels of the Texas Rangers. It was Verlander's tenth career Opening Day start and first with Houston, as all nine previous had come as a member of the Detroit Tigers. George Springer led the game off with a home run, becoming the first MLB player to lead off with a home run in consecutive Opening Days. He had homered off Felix Hernandez of the Seattle Mariners in the first inning of Opening Day 2017 at Minute Maid Park. Verlander pitched six shutout innings and struck out five. The Astors won by a final score of 4–1. Second baseman José Altuve reached 1,000 games played in his career on April 17, 2018, versus the Mariners. He became the 20th player to appear in 1,000 games for the Astros. Verlander was named AL Player of the Week on April 17. In 15 innings over one start each versus the Rangers and Twins, he struck 20 and allowed a.100 opponents' batting average. On May 7, 2018, Springer homered versus the Oakland Athletics and became the first player in Astros franchise history to record six hits in a nine-inning game. Joe Morgan had six hits in a twelve-inning game for the Astros on June 8, 1965. On May 16, 2018, Verlander threw a complete game shutout against the Los Angeles Angels for his eighth career shutout and 24th complete game. He struck out Shohei Ohtani in the top of the ninth inning for his 2,500th career strikeout, becoming the 33rd pitcher in Major League history to cross that threshold. He was second among active leaders in strikeouts behind CC Sabathia. Over three games versus the Cleveland Indians spanning May 25–27, Altuve realized a base hit in each of 10 consecutive at bats, breaking his own club record of eight which he had set the year prior. The streak included three doubles, one triple, and one home run. Verlander was named AL Pitcher of the Month for May, his fifth career award. In six starts, he produced a 0.86 ERA and.437 OPS against, allowed nine extra base hits, while striking out 50 over innings. He started and ended the month by dominating the Yankees—the only lineup in baseball with an OPS over.800—with 20 strikeouts in innings, eight hits, and one run allowed. On July 13, 2018, Charlie Morton was added to the American League roster for the 2018 MLB All-Star game making the Astros the only MLB team at the time to have all of their starting pitchers having at least one selection to participate in the MLB All-Star game. On September 26, 2018, Houston won the American League West division title after the Oakland Athletics were defeated by the Seattle Mariners, following a 4–1 win against the Toronto Blue Jays.
