Qualls was not used in a save situation Wednesday due to minor back discomfort, Evan Drellich of the Houston Chronicle reports.

The sore back cost Qualls a potential save Wednesday night, but it appears to be just a short-term issue, as manager Bo Porter said Qualls would likely be available Thursday if needed. However, consider Qualls day-to-day until he is summoned from the bullpen next.

Qualls earned his 14th save of the season Tuesday night with a clean inning against the Yankees.

Qualls, who has been shaky in relief for the Astros over the past month, struck out a batter during the appearance. The veteran reliever owns a 3.14 ERA, 1.16 WHIP and a 38:5 K:BB over 43 innings this season.

Qualls (1-3) took the loss in relief on Thursday after serving up a solo home run to Nolan Reimold in the ninth inning of a tie game against the Blue Jays. He struck out two during his inning of work.

Qualls has taken the loss in his last two relief appearances for the Astros, and while he doesn't appear to be in jeopardy of losing his job as the team's closer, Josh Fields and Jose Veras have experience in the role.

The Astros are telling other teams that Chad Qualls isn't available, CBS Sports' Jon Heyman reports.

If you're confused as to why Houston, miles outside of contention, is making a 35-year-old closer unavailable, we're with you. Qualls would have been a nice rental for a playoff hopeful. He is 1-2 with a 3.19 ERA and 11 saves in 15 chances, and is set to make a reasonable $3 million next year.

Qualls (1-2) took the loss on Tuesday after giving up five runs on four hits and a walk with a strikeout and a wild pitch over 0.2 innings against the Athletics.

Qualls has allowed seven runs over his last two relief appearances for the Astros, but he's been fantastic otherwise, posting a 3.19 ERA and 1.17 WHIP with 11 saves and a 33:5 K:BB over 36.2 innings this season.

Called on to protect a three-run lead in the ninth, Chad Qualls instead gave up five runs while recording just two outs in a blown save against the A's on Tuesday.

The inning started well enough, with Qualls striking out Steven Vogt for the first out. Qualls actually got a second out with the score 4-3, but a Yoenis Cespedes RBI single tied the game and ended Qualls' night. All told, Qualls allowed four hits, walked one and threw a wild pitch before exiting. He's now allowed runs in each of his last two appearances, sullying what was previously a very strong year for the 35-year-old.

Astros general manager Jeff Luhnow indicated Thursday that the team is unlikely to trade Chad Qualls.

Teams have expressed interest in the reliever, but Qualls will make a reasonable $6 million through the end of next season and has a $3 million option for 2016, so Luhnow doesn't feel compelled to move him. The 35-year-old boasts a terrific 1.78 ERA and 31/4 K/BB ratio over 35 1/3 innings in 2014. "I hesitate to use the word 'untouchable,' but he likes it here, he's comfortable here and he's pitching well," Luhnow said. "To have a guy who's capable of pitching late in the game, in close games, we're going to have opportunity going forward. This is a team that's improving, and as the team improves, you have more save opportunities, more opportunities to pitch at the end of close games. We need more Chad Qualls. We don't need less."

CBS Sports' Jon Heyman reports that the Tigers have inquired on Chad Qualls.

The Tigers have been connected to just about every reliever on the market. Qualls has experienced a nice bounce-back season in Houston, posting a 1.78 ERA and 31/4 K/BB ratio over 35 1/3 innings. A trade would be bad for his fantasy value, as he almost surely would be used as a setup man wherever he goes.

Chad Qualls hurled a scoreless ninth inning Monday to notch his eighth save of the season in a 4-3 victory against the Diamondbacks.

Qualls gave up a double to Ender Inciarte that was misplayed by Marwin Gonzalez, playing left field as a chain reaction to Bo Porter's decision to make a double switch that had reliever Tony Sipp in right field for one play in the eighth. Qualls has five saves since May 29 and he hasn't given up a run since way back on April 19. On that day, through six appearances, Qualls held a 9.00 ERA. It's down to 2.08. As a suddenly effective closer on a suddenly scorching team (Houston has won 12 of 16 games), the case could be made that Qualls is one of the more underrated fantasy assets in the game at the moment.

Chad Qualls tossed a scoreless ninth inning Friday against the Twins for his seventh save of the season.

Qualls worked around a two-out error by Matt Dominguez to finish off the Twins. The veteran right-hander has settled in quite nicely as the Astros' closer, notching four saves over the past eight days. He hasn't given up a run since April 19 and has allowed just one hit with an 8/0 K/BB ratio over his last 9 2/3 innings. It's time for him to be owned in more fantasy leagues.

Chad Qualls put out Paul Clemens' fire, picking up his sixth save in Thursday's win over the Angels.

Clemens loaded the bases on a pair of singles wrapped around Jonathan Singleton's fielding error before walking in a run. Qualls entered and got all three batters he faced out, allowing only one of his inherited runners to score en route to save number six on the year. Qualls has a tidy 2.29 ERA, 1.12 WHIP, and a 22/3 K/BB ratio in 19 2/3 innings.

Chad Qualls worked a scoreless ninth to pick up his fourth save as the Astros defeated the Orioles 3-1 on Thursday.

Qualls has been perfect since manager Bo Porter named him the club's official closer on May 16. The save opportunities have been few and far between, but Qualls is two-for-two with four strikeouts, no walks, and no hits in four innings since. Overall, he has a 2.76 ERA and a 1.29 WHIP.

Chad Qualls recorded the final two outs in a non-save situation against the Royals on Tuesday.

With a three-run lead, left-hander Tony Sipp was allowed to start the ninth inning to face Eric Hosmer, depriving Qualls of a save chance. Still, Qualls came in and got Billy Butler to ground out before fanning Alex Gordon to end the game. He's got the support of manager Bo Porter and a 2.93 ERA in 15 1/3 innings, so despite his status as closer of the worst team in baseball he should be owned in mixed leagues.

Astros manager Bo Porter said Friday that he will use Chad Qualls to close games.

Qualls converted the Astros' last save chance, but they've had so few opportunities that it's been tough to say who the favorite for saves is. The veteran reliever holds a 3.55 ERA and nice 15/3 K/BB ratio over 12 2/3 innings this season, though he's also posted a 1.66 WHIP. While he's far from a safe bet to keep the gig over the long haul, Qualls needs to be owned in all fantasy leagues for the time being.

Chad Qualls earned the save Sunday with a scoreless ninth inning against the Orioles.

Qualls hit Ryan Flaherty but didn't allow any other baserunners en route to his second save of the season. Qualls' only other save came on April 6, so it's hard to say who's closing games for the Astros on a day to day basis. Qualls owns a 3.75 ERA and 1.75 WHIP on the year.

Chad Qualls blew a save and took a loss as the Astros fell to the A's on Saturday afternoon.

Qualls entered the game in the bottom of the ninth inning with Houston leading 3-1 and promptly gave up a leadoff homer to Jed Lowrie. He then walked Josh Donaldson and allowed a single to Yoenis Cespedes. One batter later Alberto Callaspo tied the game with an RBI single and then Josh Reddick won it with a walkoff base hit to center field. If Astros manager Bo Porter isn't going to name a closer, he should be a little craftier with his late-inning matchups.

Astros manager Bo Porter announced that he will begin the season with a closer by committee.

Expect Chad Qualls, Matt Albers and Josh Fields to divide save opportunities at the outset, though Kevin Chapman absolutely should be owned in AL-only formats as the only projected southpaw currently in Houston's bullpen, according to the website MLB Depth Charts. Qualls is the favorite to end the season with the most saves, but that says more about his competition than it does about him. This bullpen is an absolute mess, same as last year, and the Triple-A isn't hiding any saviors.

Chad Qualls, Matt Albers and Josh Fields all pitched scoreless innings against the Cardinals on Saturday.

Manager Bo Porter is still trying to decide on a closer, and these three are his most likely options. Qualls was the favorite going in, but he's allowed four runs in seven innings this spring. Albers has allowed two runs in his seven innings, and Fields has given up just one run. While Porter will likely settle on one from the trio at the start, the ideal for the Astros is that Jesse Crain comes back strong and secures to job in late April or early May.

Chad Qualls gave up a homer to Ian Kinsler in his inning against the Tigers on Saturday.

Qualls has allowed three runs in four innings this spring. He's the favorite to close for Houston with Jesse Crain set to miss at least the first couple of weeks this season, but he is leaving the door open for someone else to take the job.

Making his spring debut, Chad Qualls gave up two runs and three hits in his inning versus the Braves on Sunday.

This after he took a blown save in an intrasquad game last week. With Jesse Crain likely to start off on the DL, Qualls is the clear favorite to begin the season as the Astros' closer. However, if he struggles this month, the door will be open for Josh Fields.