The 1975 Houston Astros season was the 14th season for the Major League Baseball (MLB) franchise located in Houston, Texas, their 11th as the Astros, 14th in the National League (NL), seventh in the NL West division, and 11th at The Astrodome. The Astros entered the season with a record of 81–81, in fourth place and 21 games behind the division-champion and NL pennant-winning Los Angeles Dodgers.

The regular season began on April 7 as the Astros hosted the Atlanta Braves with Larry Dierker making his fourth Opening Day start, which the Astros won, 6–2.

First baseman Bob Watson represented the Astros at the MLB All-Star Game and played for the National League, his second career selection. The Astros hired Tal Smith as general manager on August 7. With the Astros struggling to a 47–80 record, the team dismissed Preston Gómez, and replaced him on August 20 with Bill Virdon as the eighth manager in franchise history. The club went 17–17–1 the rest of the way.

The Astros finished last in the NL West with a record of 64–97–1, games behind the division- and World Series-champion Cincinnati Reds, also the worst record in the National League. The second time the Astros had finished in last place, the 97 losses tied the 1965 team for most in team history, was matched in 1991, and stood as the record until 2011, when they lost at least 100 games for the first time.

Following the season, center fielder César Cedeño won his fourth career Gold Glove Award.

Offseason Summary The Astros concluded the 1974 campaign with a record of , in fourth place in the NL West and 21 games behind the division-champion and NL pennant-winning Los Angeles Dodgers. This performance furthered a scintilla of three consecutive seasons with a record of .500, then unprecedented in franchise history. Center fielder César Cedeño extended his Major League record as a third successive entrant into the 20–50 club. Cedeño and third baseman Doug Rader each earned Gold Glove Awards, and right fielder Greg Gross was recognized as The Sporting News NL Rookie Player of the Year Award.

On January 5, 1975, right-handed pitcher Don Wilson died at home of carbon monoxide poisoning.

Transactions October 24, 1974: Acquired the rights of outfielder José Cruz from the St. Louis Cardinals for cash considerations. December 3, 1974: Lee May and Jay Schlueter were traded by the Astros to the Baltimore Orioles for Enos Cabell and Rob Andrews.

Uniform changes This was the first season the Astros donned their now famous rainbow uniforms. The uniforms would make slight alterations throughout the years. In 1975, the numbers on the back of the jersey were inside a white circle but by the following season, the white circle was eliminated entirely. In 1987, the rainbows were relegated to the shoulders of both home and away uniforms (prior to that they were only used on the away uniforms shoulders) and by 1994, the rainbow uniforms were retired after 19 years for a more contemporary look.

Regular season Summary April

+ Opening Day starting lineup Player Position 23 Enos Cabell Left fielder 11 Rob Andrews Second baseman 28 César Cedeño Center fielder 8 Milt May Catcher 6 Cliff Johnson First baseman 25 José Cruz Right fielder 12 Doug Rader Third baseman 14 Roger Metzger Shortstop 49 Larry Dierker Pitcher Venue: Astrodome • Final: Houston 6, Atlanta 2 Sources:

On Opening Day at the Astrodome, José Cruz introduced himself in an Astros uniform with an electric debut, going 3-for-4, swatting a home run and delivering three runs batted in (RBI) to lead a 6–2 triumph over the Atlanta Braves. Cruz singled during his first Houston plate appearance in the bottom of the second inning off Braves starter Phil Niekro for his first Astros hit, and in the bottom of the fifth, slugged a three-run home run to chase Niekro. The blast put Houston in the lead, 5–2. Rob Andrews made his major league debut at second base and struck out against Niekro during his first at bat in the first inning, and the third, singled for his first major league hit. Andrews, Enos Cabell, César Cedeño, Milt May, and Doug Rader each added two hits as Houston totaled 14. Astros starter Larry Dierker went the distance and struck out 7 to pick up his first win of the season. Dierker made his then-club record fourth Opening Day start for Houston, relinquishing a tie with the prior year's starter, Dave Roberts. Meanwhile, Rader, making his seventh consecutive Opening Day start at third base, equaled Bob Aspromonte's club record for the position (1962 to 1968). José Cruz' first home run for Houston was also the first of his career on Opening Day.

On April 13, the Astros retired Don Wilson's uniform number 40. and commemorated him during the following season with a black circular patch containing his number 40 in white, which was worn on the left sleeve of the Astros "rainbow jerseys."Patches and Armbands at exhibits.baseballhalloffame.org, URL accessed November 27, 2009. Archived November 27, 2009

May Bob Watson scored the 1,000,000th run in baseball history on May 4 during the first game of a doubleheader at Candlestick Park. In spite of Milt May's home run, Watson sprinted around the bases to cross home plate, edging ahead of Dave Concepción of the Cincinnati Reds. Meanwhile, both pitching staffs were unusually wild, issuing a record 41 bases on balls, including a single game league record of 26 in the nightcap. J. R. Richard surrendered an individual club-record eleven of the free passes; however, Houston managed to win the second game, 12–8, to obtain a split of the twinbill. Watson's prize for the historic run scored was $10,000 and one million Tootsie Rolls.

After having fallen behind on May 25 to a 6–0 score, the Astros came back in the bottom of the ninth inning to the Montreal Expos, via a leadoff home run by César Cedeño. The Expos retook the lead in the 12th inning, prior to the Astros walking it off in the bottom of the inning, 8–7.

Record-setting inning On May 31, the Astros won out in a 15–3 onslaught over the Philadelphia Phillies, erupting for a club-record 12 runs in the eighth inning. Pinch hitter Cliff Johnson fully leveraged the opportunity, hitting a home run and double that inning, which tied a modern Major League record (since 1900) with two extra-base hits in one inning.

The Phillies' starter, Wayne Twitchell—whom the Astros had selected third overall in the 1966 Major League Baseball draft—kept the Astros at bay by commencing with a two-hit shutout through seven frames, including retiring 11 in succession. Twitchell's counterpart, J. R. Richard, had surrendered two runs and four bases on balls, whiffing eight through seven innings.

In the eighth inning, José Cruz led off with a single, and Doug Rader ambushed the Phillies' defense with a bunt that allowed him to reach. With one out, Bob Watson pinch hit for Richard and singled up the middle to score Cruz, ending Twitchell's outing. Tug McGraw relieved Twitchell to face Greg Gross, for whom Johnson pinch hit. Johnson unloaded a double down the left field line that plated Rader, and an additional run scored on a misplayed relay throw to posit the Astros ahead to stay, 3–2. César Cedeño (intentional base on balls), Milt May and Enos Cabell (an RBI single each) all reached next. Hence, the Astros batted around to bring up Cruz with a 5–2 edge, who drew a walk to load the bases.

June—July On June 15, Cliff Johnson hit the second pinch-hit grand slam in franchise history, following Milt May's on May 22, 1974. Johnson's blast was a game-winner during the top of the ninth inning to stun the St. Louis Cardinals, 8–7. In the bottom of the eighth inning, St. Louis had scored thrice to take a 7–4 lead. In the bottom of the eighth inning, Joe Niekro entered with the bases loaded, and surrendered two runs by issuing a walk and allowing a sacrifice fly. However, Niekro (2–1) secured the final five outs to earn the victory. It was Johnson's first career grand slam, and sixth home run as a pinch hitter.

On June 23, the Astros took a 6-run lead over the Los Angeles Dodgers. Wayne Granger pitched the final innings; it was Granger's pickoff that ended the contest and secured a 6–5 win for the Astros.

From June 25 until August 18, Greg Gross reached base in 52 games consecutively to tie Jimmy Wynn for the franchise record. During the streak, Gross produced a .345 batting average, .427 on-base percentage (OBP) and .414 slugging percentage (SLG), garnering 70 hits and 30 bases on balls (BB). Wynn first set the record from June 4–August 3, 1969. Gross' and Wynn's streak trailed the NL record by 6 games, held by Duke Snider, who reached base at least once each game from May 13–July 11, 1954, for the Brooklyn Dodgers.

First baseman Bob Watson was invited to the MLB All-Star Game, his second career selection, and hosted at County Stadium in Milwaukee, Wisconsin. Watson pinch hit for NL starting pitcher Jerry Reuss in the fourth inning, and flied out to left field in his only plate appearance. The National League won, 6–3.

On July 21, the Astros induced four batted ground ball double plays by Joe Torre to establish an individual National League record led by righty Ken Forsch on the mound for Houston at Shea Stadium, who tossed a complete game. Félix Millán, batting second and one slot ahead of Torre in the order, went 4-for-4, garnering a single each time, which resulted as the direct conversion into the lead out on each of Torre's dubious batting events. Forsch (4–7) went on to earn victory for Houston, as he dispersed 11 Mets hits, and withstood solo blasts from Rusty Staub and Dave Kingman. Roger Metzger tripled and had 2 RBI, while Wilbur Howard socked three hits and scored twice for Houston. The final score remained the Astros 6, and Mets 2.

Rookie relief pitcher José Sosa produced a memorable first game at the plate on July 30 at the Astrodome. Taking first his major league at bat in the eighth inning, Sosa homered off Danny Frisella of the San Diego Padres, a three-run blast to lead an 8–4 Astros win. Sosa become both the first Dominican pitcher and first Houston Astro to accomplish this feat. Prior to him, José Cruz and Doug Rader also homered in the sixth inning, and Sosa closed out the final innings with a scoreless effort and two strikeouts to covert his first major league save. The next Astros player to hit a home run in his first at bat was Dave Matranga on June 27, 2003, who made a pinch hit appearance versus the Texas Rangers.

August During the nightcap of a doubleheader on August 3, José Cruz collected his first career four-hit contest. He added a pair of doubles and a pair of runs batted in (RBI). Catcher Milt May homered, tripled and had five RBI. The Astros withstood a three-run San Francisco rally in the bottom of the eighth inning to hold on for a 10–9 triumph. Jim Crawford hurled innings of relief for the win, while José Sosa earned his first hold.

On August 10, though he yielded 10 walks to the Pittsburgh Pirates, J. R. Richard navigated six innings with just one hit and two runs surrendered to lead a 5–3 Astros win. With two hits, a double, run scored, and a stolen base, César Cedeño led the way for Houston's offense.

Having performed to a major-league worst showing, on August 19, Houston replaced incumbent skipper Preston Gómez with Bill Virdon. Less than three weeks earlier, on August 1, Virdon himself had been terminated by the New York Yankees, as New York sought out the potential of installing Billy Martin. During each of Virdon's first five contests as manager, Cliff Johnson launched a home run to lead to victories in three. Moreover, an exhibition game on August 21 opposing their Triple-A affiliate, the Iowa Oaks, featured another Johnson home run.

José Cruz recorded his first career 5 RBI bout on August 23, also hitting a home run. Meanwhile, Wilbur Howard registered his first career four-hit contest.