Legendary Pitcher Remains Top of Astros All-Time Single-Season ERA Rankings

The former Houston Astros star still sits atop the single-season ERA rankings. Which pitcher is it?

Houston Astros cap | Denny Medley-Imagn Images

The Houston Astros are not a franchise to have lacked talent over the years. Last year's collapse was incredibly frustrating, considering the success they've had in recent years.

The ballclub's history has been flooded with remarkable talent and records, dating back to its expansion year. With such a long line of iconic players, it seems unfathomable that the franchise wouldn't be able to bounce back.

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Using baseball-reference.com, we've put together the top five all-time single-season ERA rankings in franchise history. Unsurprisingly, one of their most notable pitchers still sits atop the rankings.

5. Danny Darwin (2.21 ERA in 1990)

Cincinnati Reds 2018 interim pitching coach Danny Darwin | David Richard-Imagn Images

After spending seven years with the Texas Rangers, Darwin played with the Milwaukee Brewers before they shipped him out to the Astros in exchange for Don August and Mark Knudson in August 1986. From there, he went on to play in Houston for six seasons.

During that period, he recorded a stunning 2.21 ERA in 1990, with 109 strikeouts across 162.2 innings pitched through 48 games, 17 of which he started. His ERA that year remains among the franchise's top five in a single season.

4. Bob Knepper (2.18 ERA in 1981)

Houston Astros cap | Brett Davis-Imagn Images

Knepper was picked 43rd overall in the second round of the 1972 MLB draft, picked by the San Francisco Giants, where he played for five years before heading to the Lone Star State. The 1981 season marked his first year in Houston, and what a year it was.

He wrapped up the season with a 2.18 ERA and 75 strikeouts across 156.2 innings pitched through 22 starts. Compared to his ERA the year before, 4.10, this was a substantial improvement, and a rather shocking one at that.

3. Roger Clemens (1.87 ERA in 2005)

New York Mets Dwight Gooden and Boston Red Sox Roger Clemens | Frank Becerra Jr./The Journal News / USA TODAY NETWORK via Imagn Images

When looking at Clemen's 24-year career in the Major Leagues, his three-year stint with the Astros is just a brief period. But that doesn't mean it wasn't notable. In fact, in 2005, in his second year with the ballclub, he logged a career-best ERA of 1.87.

The closest he had come to a 1.87 ERA was back in 1990 when he was playing with the Boston Red Sox, registering a 1.93 ERA. Making matters more impressive, his time in Houston was toward the end of his career. He was no longer in his baseball prime, but he was still able to post elite performances on the mound.

2. Justin Verlander (1.75 ERA in 2022)

Houston Astros starting pitcher Justin Verlander | Ken Blaze-Imagn Images

It's always refreshing to see active players land among baseball's greats. Before being traded to the Astros, Verlander spent 13 years with the Detroit Tigers, rising to become a notable name in the Major Leagues.

In August 2017, he found himself being sent to Houston, where he continued to develop, eventually posting a shocking 1.75 ERA during his 2022 campaign. Of course, his performance with the franchise played a key role in Houston finding its way to the World Series and ultimately clinching the titles in 2017 and 2022.

1. Nolan Ryan (1.69 ERA in 1981)

Former Texas Rangers, Houston Astros pitcher Nolan Ryan | Tim Heitman-Imagn Images

When dedicated fans think of legendary players in Astros history, Ryan often comes to mind. In his 27 years in professional baseball, nine of them were spent with Houston. This isn't where he started, nor is it where he ended, but these were transformative years in his career.

His most productive season with the ballclub was in 1981, when he registered a shocking 1.69 ERA and 10 strikeouts across 149.0 innings pitched through 21 starts. To this day, he holds the helm at No. 1 among the Astros all-time single-season ERA rankings.