Here is Brian McTaggart’s ranking of the Top 5 left-handed starting pitchers in Astros history:
1. Dallas Keuchel (2012-18)
Key fact: Keuchel is the only lefty in franchise history to win a Cy Young Award
A fledging starter for the rebuilding Astros from 2012-13, Keuchel narrowly made the starting rotation to begin the ’14 season and suddenly saw his career take off. A ground-ball specialist, he went 12-9 with a 2.93 ERA in 29 starts that season before going 20-8 with a 2.48 ERA in 33 starts in ’15 to win the American League Cy Young Award while helping the Astros reach the playoffs.
Not only did Keuchel start the All-Star Game in Cincinnati in 2015, he threw a gem in the AL Wild Card Game at Yankee Stadium to send the Astros to the next round. After a down season in ’16 (9-12, 4.55 ERA), Keuchel recaptured his All-Star form in ’17 by going 14-5 with a 2.90 ERA in 23 starts and helped the Astros win their first World Series title. He missed six weeks that season because of a neck injury.
Before signing with Atlanta in the middle of the 2019 season, Keuchel went 76-63 with a 3.66 ERA in 192 games (182 starts) for the Astros and won four AL Gold Glove Awards (2014-16, ’18). In 10 postseason games (nine starts) with Houston, he was 4-2 with a 3.31 ERA.
2. Mike Hampton (1994-99, 2009)
Key fact: With 22 wins in 1999, Hampton holds the single-season club record
The bulldog pitched atop the Astros’ rotation for five seasons, helping the Astros win three National League Central division titles (1997-99). The Astros stole Hampton in a trade with the Mariners following the ’93 season, sending outfielder Eric Anthony to Seattle, and quickly saw Hampton become entrenched in the rotation of a team on the rise.
Hampton went 76-50 with a 3.59 ERA in 216 games (172 starts) with the Astros, culminating with a fantastic season in 1999 in the final year of the Astrodome. Hampton went 22-4 with a 2.90 ERA and finished second in the NL Cy Young race to Randy Johnson, who had finished the previous season in the Astros’ rotation with Hampton before signing with Arizona.
With one year left on his contract, Hampton was dealt to the Mets in December 1999, along with slumping outfielder Derek Bell, in exchange for outfielder Roger Cedeno, rookie right-hander Octavio Dotel and Minor League left-hander Kyle Kessel. Hampton returned to the Astros for one year in 2009 and was 7-10 with a 5.30 ERA in 21 starts.
3. Bob Knepper (1981-89)
Key fact: Knepper holds the club record for wins by a lefty (93)
Acquired in December 1980 from the Giants in exchange for infielder Enos Cabell, Knepper went on to start 267 games for the Astros -- fifth-most in club history and most by a lefty -- and won at least 14 games in four different seasons. After back-to-back 15-win seasons in ’84 and ’85, Knepper went 17-12 with a 3.14 ERA in 40 games (38 starts) in ’86. He lost a 3-0 lead in the ninth inning of Game 6 of the NL Championship Series against the Mets, who won the game in extra innings to advance to the World Series.
Knepper, who was haunted by poor run support during his time in Houston, made his second All-Star team in ‘88 but was released halfway through the ’89 season. His 100 losses are the third-most in club history behind Larry Dierker (117) and Joe Niekro (116).
4. Framber Valdez (2018-25)
Key fact: His 81 wins are second-most by a lefty in club history
A workhorse left-hander who was an anchor atop the Astros' rotation for half a decade, Valdez threw at least 190 innings in three seasons, including an AL-best 201 1/3 innings in 2022. That season marked the first of his two consecutive All-Star Game selections. He finished fifth in the AL Cy Young voting '22, ninth in '23 and seventh in '24, when he was 15-7 with a 2.91 ERA. He threw a 93-pitch no-hitter against Cleveland on Aug. 1, 2023, and came within one out of a second no-hitter a season later.
Signed out of the Dominican Republic for $10,000 at 21 years old, he won seven career postseason games for the Astros, including two in the 2022 World Series. He held the Phillies to one run in 6 1/3 innings in Game 2 and one run in six innings in the clinching Game 6 win in Houston, striking out 18 batters in 12 1/3 innings.
5. Wandy Rodriguez (2005-12)
Key fact: His 80 wins are third-most by a lefty in club history
Signed out of the Dominican Republic in 1999, Rodriguez became a steady and dependable starter for the Astros for nearly a decade, reaching 10 wins in a season four times. As a rookie, he threw 3 1/3 innings in relief of Roger Clemens in Game 1 of the 2005 World Series and took the loss.
Rodriguez went 80-84 with a 4.04 ERA in 227 games (218 starts) with the Astros and ranks 10th in career games started and 11th in games won in club history. He was traded to the Pirates in 2012 as the Astros were beginning their rebuild.
Honorable mention
• Jim Deshaies (1985-91) went 61-59 with a 3.67 ERA in 181 games (178 starts) for the Astros before becoming a popular television announcer with the club. He had a bang-up rookie season in 1986, helping the Astros win the NL West division title. He was 12-5 with a 3.25 ERA and tied a Major League record when he struck out the first eight batters he faced in a game against the Dodgers on Sept. 23, 1986, at the Astrodome.
• Randy Johnson came to the Astros in a blockbuster deal at the 1998 Trade Deadline and went 10-1 with a 1.28 ERA in 11 starts, including four shutouts, in August and September. He was terrific in the playoffs, too, posting a 1.93 ERA while striking out 17 over 14 innings in two starts against the Padres, but he lost both games because the Astros managed only one run when he was on the mound. He signed with the D-backs following that season and proceeded to win four consecutive NL Cy Young Awards to cement his Hall of Fame career.
• Andy Pettitte signed with his hometown Astros before the 2004 season and went 37-26 with a 3.38 ERA in 84 appearances (83 starts) over three seasons. He underwent arm surgery and missed the ’04 playoffs but had a terrific season in ’05, going 17-9 with a 2.39 ERA and finishing fifth in the NL Cy Young voting. He won 14 games in ’06, then finished his career back with the Yankees.
• Dave Roberts won 47 games over four seasons, 1972-75, including 17 in ’73. In ’74, he beat Hall of Famer Steve Carlton of the Phillies in a game that lasted 1 hour, 26 minutes.
• Mike Cuellar went 37-36 with a 2.74 ERA with 38 complete games for the Astros from 1965-68. The Astros traded him to the Orioles before the ’69 season and watched him win the AL Cy Young Award that season by going 23-11 with a 2.38 ERA. That was one of four 20-win seasons he had in Baltimore, where he won 143 games in eight years.