ARLINGTON -- The Rangers lost on Sunday, 8-7 to reigning World Series champion Houston at Globe Life Park, and were swept in the four-game series when closer Keone Kela balked in the winning run in the ninth inning.

That was not the worst moment of the day for the club's overall pitching. Not even close.

Consider that:

-- Left-hander Matt Moore, the most hittable pitcher in the majors, allowed a homer by George Springer on his first pitch of the game and never recovered.

"Not my favorite way to start a game," Moore said.

Moore gave up six run in three innings, raising his ERA to 7.88. He has the highest batting average against (.353) and slugging percentage (.566) among major-leaguers with 50 innings.

"It was challenging for him," manager Jeff Banister said.

-- Moore nonetheless remains in the rotation because the Rangers are strapped to find a replacement for another starter: right-hander Doug Fister, put on the disabled list because of a strained right knee. Fister is expected to be out longer than the minimum 10 days.

"We have to make plans to have somebody else in that spot," Banister said. "I don't foresee this being a 10-day event."

The pool of candidates listed by Banister included former Rangers right-hander Yovani Gallardo, trying to get back to the majors at age 32.

That is a telling statement about the state of pitching in the upper levels of the organization. There is not much there now, as the Rangers have acknowledged.

They could try Gallardo or 33-year-old right-hander Austin Bibens-Dirkx, who has made two starts with the Rangers this season. The "prospect'' possibilities are left-hander Yohander Mendez and right-hander Ariel Jurado.

Mendez is 0-6 with a 5.26 ERA in 51 1/3 innings with Triple-A Round Rock. Jurado is 2-2 with a 3.61 ERA at Double-A Frisco but has allowed 13 runs and 23 hits in 10 1/3 innings in his last two starts.

Gallardo, with the Rangers in 2015, went to spring training with Milwaukee on a minor-league deal and took his release on March 26. He signed with Cincinnati and was hit hard in three relief appearances, allowing eight runs in 2 1/3 innings. In his last 45 major-league appearances, Gallardo is 11-18 with a 5.81 ERA.

The Rangers signed Gallardo to a minor-league deal after he refused an outright minor-league assignment with Cincinnati.

Gallardo is 2-1 with a 3.81 ERA for 10 starts in the hitter friendly Triple-A Pacific Coast League with Round Rock. He started on Friday at Las Vegas and gave up only one run in five innings in a park that is hard on pitchers. Banister said reports indicate Gallardo "has thrown the ball well."

While pondering how to replace Fister, the Rangers wrestle with the season-long dilemma of Moore. The Rangers and Moore are no closer to an answer today than they were on the first day of spring training.

"If there was something that I knew I needed or somebody around us knew what I needed, we'd go there," Moore said. "This is the way baseball goes sometimes. I hope it's not going to continue this way."

The Astros jumped on Moore's fastball and cutter early, going 5 for 6 with those pitches in the first two innings.

It has been that way all season for Moore. According to brooksbaseball.net, opponents are hitting .375 for 120 at-bats when putting the fastball in play and .448 for 29 at-bats when putting the cutter in play.

"Obviously, I'm not happy with it," Moore said. "But I'm not going to bury myself. I have to keep working through things."

The Rangers' rotation allowed 19 runs in 21 1/3 innings during the series with the Astros. Yovani Gallardo to the rescue.