The ballclub, which came away with a share of the American League West lead over the weekend in Seattle, announced it selected Aledmys Diaz to the major league roster and optioned Grae Kessinger to Triple-A Sugar Land.
Diaz was tabbed to start at first base against Oakland in the series opener. He is sporting No. 12 for his second stint in Houston after going with No. 16.
The Astros designated David Hensley for assignment.
Houston signed Diaz to a minor-league deal on July 13, a week after Oakland, his previous team, released him. Diaz, a 33-year-old Cuban native, former All-Star, and utility player, is a nine-year major league veteran, previously spending four seasons with the Astros starting in 2019.
Diaz, typically an infielder, won a ring as part of Houston's 2022 World Championship season and later signed a free-agent deal with the Athletics heading into 2023. He also played on the Astros' 2019 and 2021 World Series teams.
Diaz's entrance came at the price of Hensley's exit from the organization that drafted him in 2018.
SEE MORE: Parents of Houston Astros infielder David Hensley witness 'surreal' moment as son makes MLB debut
The 28-year-old most notably played with the Astros during the 2022 world title season when the ballclub called on him mainly as a designated hitter. Hensley played 46 games on the major league roster over two seasons in Houston. The infielder's hit-by-pitch in Game 1 of the 2022 American League Division Series was instrumental in setting up Yordan Alvarez's walk-off homerun victory.
SEE MORE: Meet David Hensley, tile shop worker-turned-World Series starter for the Houston Astros
Hensley spent the current season with the Sugar Land Space Cowboys.
Mariners fan grabs Yordan Alvarez's historic home-run ball
Diaz has seen firsthand the power of his reunited teammate and fellow countryman Yordan Alvarez, who now has hitting for the cycle as part of his resume.
In order, No. 44 collected a single, a home run, a triple, and a double off Mariners pitching on Sunday during Houston's loss against Seattle.
In particular, the homer was a 429-foot upper-deck shot that fell into the hands of Seattle fan Amy Franz, who posted a photo of herself and the historic baseball on X, the social platform formerly known as Twitter.
However, Franz wasn't seeking the highest bidder for a hall of fame-worthy artifact.
"Dear (Astros and Mariners) I have Yordan Alvarez Home Run Ball. It's worth more to him than me being as he hit for the cycle. Please find a way for me to get it to him," Franz posted.
MLB.com reports that Alvarez retrieved his double and home run balls, and Franz got a great memory in return: a photo with the All-Star and a signed ball.
"I was able to congratulate Yordan and give him the piece of history that he earned," Franz said. "I did not ask for anything in return, but he made sure that I received an autographed ball to show his appreciation."
Even amid a bitter race for the division, the Astros and their fans saluted their rival supporter with retweets and replies to Franz's posts.
"(Astros) fan here, but mad props to you, Amy. That's a class move ... my respect for Mariners fans," X user @chrish23 replied.
SEE ALSO: Astros end an era with Oakland Athletics