He wasn't expected to be available for Saturday's matinee against the Astros after yielding a run and throwing 35 pitches in a shaky save Friday night, and he might not pitch until after Oakland's off-day on Monday.
All players, even those who set franchise-best consecutive-saves streaks, as Balfour did earlier this year with 44 dating back to last season, are prone to periods of poor play, but the A's hunt for a second straight AL West title with less than a month left in the season is not an ideal point to be experiencing such difficulties.
Is this merely a brief scuffle, or something bigger that requires more attention?
"If you want me to go out there and be perfect every time, it's not going to happen," Balfour said.
While the stat sheet might indicate that Balfour was particularly rough on Friday with two hits and a run allowed by the Aussie, a closer look clarifies that of the 35 pitches he threw, only one left the infield. Houston's first single was of the infield variety, and the second hit was a soft single to right field.
Then Eric Sogard committed a fielding error on a force attempt that allowed the Astros to score before Balfour ended the inning with two consecutive outs on a force at second a swinging strikeout.
"Granted, his stuff might not have been as crisp as we've seen earlier in the year, but there are going to be periods in time when guys struggle a little bit and it's not only just the closer," A's manager Bob Melvin said. "It's more magnified, as I've said before, when it is the closer because he's the last line of defense. But everybody's going to go through periods where they struggle some during the course of the season."
"You have to stay confident with those guys and sometimes you have to let them fail," Melvin added. "If you're too quick to do that then it shows you don't have confidence in them. ... There's 162 games and you're not going to be perfect."
Jeff Kirshman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.