Harden said he felt better on Thursday, but not well enough to throw the bullpen session he'd need to take the ball in Baltimore.
"'Better' is a term I despise," Macha said. "I want to hear 'good,' 'great,' 'outstanding.'"
Macha wouldn't say who'll start for the A's on Saturday, reiterating only that it will be either lefty Joe Kennedy, who has worked exclusively out of the bullpen since being acquired July 13, or righty Juan Cruz, who is 4-1 with a 2.65 ERA at Triple-A Sacramento this season.
The A's had been leaning toward Cruz, whom they asked River Cats manager Tony DeFrancesco to limit to four innings Tuesday night, but it now appears likely that Kennedy will get the nod.
A source in Sacramento said that Cruz was told Tuesday that he was going to be called up, but told a day later that the move was on hold. Kennedy, who was 4-8 with a 7.04 ERA in 16 starts with Colorado before the trade, is 1-1 with a 4.24 ERA -- and, more significantly, a .208 opponents' batting average against the players on the Orioles' current roster -- in seven career games against Baltimore, including seven innings of shutout work against them last year during Interleague play.
If Kennedy gets the call, the A's will recall lefty reliever Ron Flores and likely demote seldom-used infielder Keith Ginter.