On August 21, Mike Fiers tossed a no-hitter versus the Los Angeles Dodgers, the 11th in club history, and first-ever accomplished at Minute Maid Park.

[2] On January 6, 2015, results for the National Baseball Hall of Fame and Museum voting revealed that Craig Biggio had been inducted on his third ballot, becoming the first Houston Astro to be so honored.

[3] After a five-year gap in contact with the Astros organization,[17] former first baseman Jeff Bagwell accepted a formal invitation from Hinch to be a guest instructor in spring training.

[18] Starting pitcher Asher Wojciechowski (0–1) made his major league debut on April 9, ceding four runs on eight hits in four-plus innings as the Astros fell to Cleveland, 5–1.

[21] On April 14, right fielder George Springer's over-the-wall catch robbed Leonys Martín of a walk-off grand slam in the 10th inning at Globe Life Field in Arlington.

[28] Lance McCullers Jr. made his major league debut on May 18 as the starting pitcher versus the Oakland Athletics, surrendering one run, three hits, three walks, and struck out five over 4+2⁄3 innings.

Keuchel went 4–1 W–L in six May starts, produced a 2.62 ERA and 38 strikeouts in 44+2⁄3 innings while surrendering a .223 batting average against, and closed the month with successive complete games, including a four-hit, 11-strikeout shutout of the White Sox at Minute Maid Park.

[30] On June 3, the Astros overcame the Baltimore Orioles, 3–1, led by McCullers' first career complete game in his fourth start to go along with a first-time 11 strikeouts.

In the eighth inning, Pat Neshek issued a two-out base on balls to Justin Smoak which ended 24 consecutive appearances without a walk, the second-longest streak to open a season in major league history.

[37] On June 9, Correa singled in the sixth against Chicago and stole his first base before hitting his first MLB home run off Zach Duke in the ninth inning.

[38] On June 10, Velasquez made his major league debut, stifling Chicago over five shutout innings, and Springer attained his first career five-hit game.

[Note 3] In spite of these achievements, the White Sox homered in each of the sixth, seventh, and eighth innings for a 4–1 decision over Houston and three-game sweep, running the Astros' losing streak to a season-high seven.

[39] Powered by home runs from the quartet of Tucker, Correa, Jake Marisnick, and Carter, the Astros ended June 17 victorious at Coors Field, 8–4.

[40] With three stolen bases versus the Colorado Rockies in his tenth MLB game on June 18, Correa became the second-youngest player to do so over the preceding century, trailing only Rickey Henderson by 21 days.

Correa became the sixth Astro to receive the monthly award, joining teammates McHugh, winner for the previous September, and Springer, who won in May 2014.

[22] Longtime Houston Astro Craig Biggio, who was a Hall of Fame electee for the class of 2015, delivered a thoughtful and commanding induction speech on July 29, 2015, that can be seen here.

Randy Johnson, who spent the latter part of the 1998 season in Houston, pitched some of the best baseball of his career including a 1.28 ERA and four shutouts, made his Hall of fame speech.

[48] With one out in the bottom of the ninth on July 23, Altuve's walk-off home run gave the Astros a 5–4 victory over the Boston Red Sox, the final of his four hits.

Jason Castro hit a walk-off, three-run home run with two outs in the bottom of the ninth to secure a 3–0 win and three-game sweep of the Angels.

[54] Adrián Beltré made history against the Astros on August 3, and McCullers endured the shortest outing of his career as the Rangers won out in a slugfest, 12–9.

[Note 6][56] On August 18, Marwin González belted his first career walk-off home run to punctuate a 3–2 win while making his first start of the year in left field.

He went 3-for-4, adding a double and two RBI versus the Tampa Bay Rays before his leadoff blast in the bottom of the 10th inning off All-Star closer Brad Boxberger.

[57] Mike Fiers, making his third start for the Astros, pitched a no-hitter versus the Los Angeles Dodgers to lead a 3–0 win on August 21.

In fact, per the Elias Sports Bureau (ESB), Fiers' sterling outing made him the first since the Texas Rangers' Jim Bibby in 1973 to have changed teams mid-season and author a no-hitter.

[60] On August 25, the Astros won a tense contest at Yankee Stadium, 15–1, led by Keuchel's seven shutout innings and Gattis' and Gómez' one-home run, four-RBI performances apiece.

Lowrie's home run capped the Astros' five-run 9th inning rally off AL saves leader Huston Street (3–3) for a 5–3 victory, evading a four-game losing streak while also battling the Angels for a wild-card berth.

Prior to Keuchel, rotation mates Dave Ferriss and Tex Hughson jointly held the record while with the 1946 Red Sox, each going 13–0 at Fenway Park.

[74] The Astros' regular season ended with a 5–3 loss to Arizona; however, they qualified for the playoffs for the first time since 2005 with an 86–76 record, securing a trip to Yankee Stadium to face New York in the AL Wild Card Game.

Keuchel, who had never had pitched on three days' rest prior to the Wild Card Game, stifled the Yankees with three hits allowed over six innings to lead a 3–0 Astros win.

In the seventh inning, Jonathan Villar pinch-ran for Chris Carter, stole second base, and scored on a single by Jose Altuve for the final run of the contest.