The 2013 Houston Astros season was the 52nd season for the Major League Baseball (MLB) franchise located in Houston, Texas, their 49th as the Astros, and 14th at Minute Maid Park. Further, it was the Astros' inaugural season as members of both the American League (AL) and AL West division, after having spent their first 51 seasons in the National League (NL). The Astros entered the season with a 55–107 record and last-place finish in the NL Central division, 42 games behind the division-champion Cincinnati Reds, their most losses recorded to date.

The 2013 season was the first for Bo Porter as manager, the 21st in Astros' franchise history, succeeding Tony DeFrancesco. On March 31, the Astros won their first contest and Opening Day as an American League team, 8–2, while hosting their in-state rivals, the Texas Rangers, also the 4,000th win in franchise history. Bud Norris was the Astros' Opening Day starting pitcher. In the first round of the June MLB draft, the Astros selected pitcher Mark Appel as the first overall pick.

Catcher Jason Castro represented the Astros at the MLB All-Star Game and played for the American League, his lone career selection. On July 19, outfielder Brandon Barnes hit for the cycle while going 5-for-5 for the eighth cycle in franchise history.

The Astros concluded their regular season with a 51–111 record, in last place the AL West, 45 games behind the Oakland Athletics, and as well as most losses in the major leagues. This was Houston's fourth consecutive season since with more defeats than the year prior and their unprecedented third successive 100-loss season, another new club record for losses, and fewest wins by any MLB club since the 2004 Arizona Diamondbacks, who had an identical 51–111 record.

Offseason The Houston Astros concluded the campaign with a record, in sixth and last place in the National League (NL) Central division, 42 games behind the division-champion Cincinnati Reds.

With Houston moving from the National League (NL) to the American League (AL), the structure in MLB shifted 16 of 30 teams occupying the NL to five teams in each of baseball's six division. The AL West, the gaining division, had four teams prior to the move, while the NL Central, the donor group, had six. Hence, the move equaled the number of teams to 15 in each league. The Astros became the first franchise since the 1998 Milwaukee Brewers to switch leagues. Milwaukee had joined Houston in the NL Central division, adding the sixth team in the division.

Regular season Summary Inaugural game in the American League

+ Opening Day starting lineup Player Position 27 Jose Altuve Second baseman 29 Brett Wallace First baseman 23 Chris Carter Left fielder 12 Carlos Peña Designated hitter 44 Justin Maxwell Center fielder 15 Jason Castro Catcher 30 Matt Dominguez Third baseman 2 Brandon Barnes Right fielder 13 Ronny Cedeño Shortstop 20 Bud Norris Pitcher Venue: Minute Maid Park • Final: Houston 8, Texas 2 Sources:

Houston's first-ever Opening Day as an American League club took place on March 31, where they hosted in-state rivals, the Texas Rangers, at Minute Maid Park. As a result of moving to the American League, Houston's rivalry with Texas transformed from interleague to intradivision. The Astros claimed victory, 8–2. Former Astro Lance Berkman, starting as the Rangers' designated hitter (DH), was recognized during the pre-game ceremony. Texans defensive end J. J. Watt threw the ceremonial first pitch to catcher J. D. Martinez, who promptly obliged Watt by autographing a baseball. Bud Norris was the Astros' choice as the first Opening Day starting pitcher for the AL era, thus delivering the first pitch.

The Astros' first hit as AL team came via Altuve's groundball single in the first inning. Justin Maxwell connected for a two-run batted in (RBI) triple during the bottom fourth to break a scoreless tie. The first pinch-hitting decision arrived in the sixth inning for manager Bo Porter, with runners on first and second and two outs. The actor in Porter's move became Rick Ankiel, substituted for Brandon Barnes, and Ankiel launched Houston's first home run as an AL team, a three-run blast to right field, to give the Astros a lead of 7–2. Maxwell tripled twice, which tied a major league record for Opening Day. The Astros' first victory as an American League club was also the 4,000th in franchise history. Moreover, this win was the first of what evolved into a club-record ten-Opening Day winning streak, through 2022.

April On April 2, Marwin González broke up a perfect game bid by Rangers starter Yu Darvish with two outs in the bottom of the ninth inning. Darvish struck out 14 and achieved a game score of 96. Michael Kirkman relieved Darvish and gave up another hit to Jose Altuve. However, the Astros' rally stalled as Kirkman secured the final out and victory for Texas, 7–0. Lucas Harrell (0–1) took the loss in spite of being charged with just one run over six innings pitched.

For the third time in a single game on April 9, the Astros concentrated as many as 40 total bases during a 16–9 route of the Seattle Mariners. A quartet of Astros went deep for the first time on the season Chris Carter (twice), J. D. Martinez, Marwin González, and Jose Altuve. Seven of nine starters assembled multi-hit efforts as the Astros collected 22 hits, eight going for extra bases. Right-hander Paul Clemens (1–0) earned the victory with four innings of relief though he surrendered five earned runs and three home runs. Carter attained both his first career multi-homer and four-hit games, while for Altuve, it was his third career four-hit game and first with four runs batted in. González reached base five times via three hits and two walks and scored thrice. The 16 runs scored represented a season-high for the team. The 40 total bases ranked, at the time third-most in club history (44 accumulated on September 9, 2000; and 42 one month earlier on August 13, 2000). The Astros' next bout attaining this threshold was on August 10, 2019, when they set a new franchise record with 50.

The Cleveland Indians handed the Astros a 19–6 defeat on April 20 at Minute Maid Park, their highest score surrendered on the season. Astros starter Philip Humber (0–4) recorded just one out while being pasted for eight runs on eight hits. Following Humber, the Indians battered Dallas Keuchel for another seven runs over innings, striking a 14–0 lead after just two at bats on their way to scoring at least one run in each of the first five innings. Paul Clemens parlayed the lone bright spot for Houston pitching, delivering one-hit ball over the final frames.

May Jason Castro honered twice on May 25, he second career mult-home run game.

Castro attained his first career four-hit game on May 24.

For the week ended May 26, Castro batted .579 / .636 on-base percentage (OBP) / 1.105 slugging percentage (SLG) (11-for-19), 21 total bases, three home runs, five runs batted in (RBI). Hence, Castro was named AL Player of the Week.

On May 27, J. D. Martinez became the second Astro to earn the platinum sombrero, a mythical award for striking out five times in one game. His followed Preston Wilson on April 17, 2006, a nine-inning game. Martinez' was during a 12-inning victory over the Colorado Rockes, 3–2. Brandon Barnes sliced a ground rule double to deep right field to score Ronny Cedeño during the bottom of the 12th inning for the walk-off victory.

June On June 18, Matt Dominguez connected for his first grand slam in the major leagues, off Tom Gorzelanny of the Milwaukee Brewers.

On June 23, Chris Carter attained his second career four-hit game—and second of the campaign—while realizing his first with three doubles. In spite of this performance, Houston fell in defeat to their former National League Central-division rivals Chicago Cubs, 14–6. Jeff Samardzija (5–7) earned the win over Jordan Lyles (4–2) while Ryan Sweeney collected six RBI, and Anthony Rizzo augmented four hits, four RBI, through three hits.

Beginning of July Jason Castro was invited to the MLB All-Star Game for the first time, hosted at Citi Field in Queens, New York City. He became Houston's second catcher to garner selection to the All-Star Game, succeeding Craig Biggio in 1991.

Brandon Barnes' cycle

On July 19, outfielder Brandon Barnes hit for the cycle, the eighth in franchise history, including a 5-for-5 performance and an inside-the-park home run in the second inning during a 10–7 loss to the Seattle Mariners. Barnes followed up the home run with a triple in the fourth, single in the sixth, and double in the eighth. In the ninth, he singled for the fifth hit of the day.

This was the only cycle in club history featured as portion of a five-hit game, and just the third five-hit game in club history also accentuated by 10 or more total bases. The seventh Astro to hit for the cycle, the only player to do so twice was César Cedeño. Barnes' feat was preceded by Luke Scott on July 28, 2006, and Barnes' then-teammate Jose Altuve succeeded him on August 28, 2023.

Rest of July Multiple Astros realized first-time achievements on July 31 in Oriole Park at Camden Yards, led by Jason Castro, who connected for his first major league grand slam. He hit it off Miguel González of Baltimore during the top of the fourth inning to cap an 11–0 Astros victory. Castro also doubled twice, and Robbie Grossman (1) and Matt Dominguez (14) added home runs. Brett Oberholtzer tossed seven shutout innings to obtain his first major league victory and a game score of 77. Dominguez produced his first career four-hit game, while Grossman's home run was his first in the major leagues. Castro also started a 12-game hitting streak which was second-highest on the Astros this season, and lasted until August 14. He hit .370. / .455 / .587, four doubles, two home runs, 10 RBI, and 8 BB.

August From August 13 to 27, rookie Robbie Grossman produced a team season-high 14-game hitting streak. Grossman batted .365 / .369 / .492, 17 hits, 5 doubles, one home run, and 9 RBI.

September On September 28, former Astro Andy Pettitte made his final major league appearance at Minute Maid Park, earning a five-hit complete game victory as the New York Yankees defeated the Astros, 2–1. The Astros scored their lone run during the bottom of the fourth inning when Chris Carter drove home Jose Altuve on a groundout. J. D. Martinez doubled for the only extra-base hit off Pettitte. Pettitte whiffed Brandon Barnes in the eighth for his final major league strikeout. During the bottom of the ninth, Carter singled for the final hit off Pettitte, and Pettitte retired Martinez on a ground out to third base for his final batter of the contest and major league career.

The Astros concluded the 2013 season on a 15-game losing streak, qualifying as the longest-ever in franchise annals.

Performance overview

During an up-and-down first season as members of the American League, the Astros' 15-game losing streak, plunging their performance to a club-worst 111 losses. On the season, Houston won just 12 series, two of which were sweeps, and none outside of the AL West. They were swept 18 times, finishing 45 games out of first place, winning just two games against the rival Texas Rangers and four games against the Oakland Athletics, getting shut out 14 times (twice in a row against the Rangers and the Rays). They surrendered 10 runs or more in 17 games.

For the third consecutive year, the Astros set the club record for losses, surpassing the 56–106 record the year prior. They finished 45 games behind the AL West-champion A's. The 45 games behind surpassed another club record set in 1975, when they trailed by games to that year's National League West division-champion Cincinnati Reds, who claimed an incredible record along with that year's World Series. They became baseball's first team to lose 100 or more contests over three consecutive years since the 2004 to 2006 Kansas City Royals.