HOUSTON – In the toughest stretch of the season, one of baseball’s best bullpens has to make do without its set-up man.

Right-hander Ryan Pressly was placed on the injured list on Saturday with the Houston Astros after suffering a strained lower back. Pressly attempted to pitch despite the discomfort in his club’s last road game.

“I don’t think it’s serious,” manager Joe Espada said Saturday afternoon. “We just decided to give him some time to heal and then he can get back on the field.”

Espada said Pressly had not undergone any imaging tests and the club was confident that time off would ease the pain.

The placement is retroactive to Wednesday, meaning Pressly won’t be eligible to play again until Aug. 29, when Houston opens a four-game series against the Kansas City Royals. He will miss the entire Astros’ upcoming road trip through Baltimore and Philadelphia, which may be the toughest seven games of the season for Houston.

Pressly last pitched on Tuesday against the Tampa Bay Rays, a laborious 32-pitch outing in which velocity dropped on all four pitches. Pressly was not seen at Minute Maid Park before Saturday’s game against the Chicago White Sox and was therefore unavailable for comment.

The loss of Pressly extends a spate of injuries on the Astros’ pitching staff, which already has six starters on the injured list. Houston’s bullpen had remained relatively healthy throughout this ill-fated season, but the first notable injury came at the worst possible time.

Friday’s 5-4 loss to the White Sox kicked off a streak of 18 consecutive games for the Astros, 11 of which are against teams that entered Saturday at least 12 games over .500. Houston also plans to use a six-man starting rotation, which will take an arm out of the bullpen and put more pressure on the middle relievers to compensate for Pressly’s absence.

Bryan Abreu is likely the Astros’ set-up man with Ryan Pressly out. (Ron Jenkins / Getty Images)

Logic suggests Espada will slide Bryan Abreu into the eighth-inning closer Josh Hader’s role, but how the manager will maneuver the middle innings in his first year is far more mysterious. He must also be aware that entering Saturday, Abreu has already made 60 appearances this season, one fewer than the major league leader.

“There are going to be some games where Abreu and Hader aren’t going to be available, so it would be great if we could get some of those guys to keep throwing the ball like they have been,” Espada said.

Since May 1, only the Cleveland Guardians and Milwaukee Brewers have a lower bullpen ERA than the Astros, a testament to the depth created by various waiver claims, minor league additions and in-house relievers. Of them, Kaleb Ort and Tayler Scott are the most logical candidates to throw leverage innings in Pressly’s place.

Scott, who signed a minor league contract this winter, has been one of the season’s biggest revelations. Scott entered Saturday’s game with a 1.75 ERA — only 10 qualified relievers have a lower one — but has struggled with the same workload issues as Abreu. Scott’s 52 appearances are just two shy of his career high, which he set in 2017.

Ort, who was claimed off waivers by the Orioles in late May, has allowed just one earned run in his first 11 2/3 innings as an Astro. Seth Martinez, who Houston acquired from Triple-A Sugar Land to take Pressly’s spot on the active roster, has also established himself as one of the best right-on-right relievers in baseball and could contribute some leverage innings.

Pressly had allowed a run in each of his final four appearances before going on the injured list, pushing his ERA to 3.86 in 49 appearances. Pressly’s 45th appearance of the season on August 2 earned him a $14 million club option for the 2025 season, but the option will be void if Pressly finishes the season on the injured list.

(Photo: Jack Gorman/Getty Images)