"We've got a couple of different guys in-house. We'll see who lines up," Hurdle had said.
The manager corrected himself on Tuesday, explaining, "When I said 'in-house,' I didn't just mean somebody on the club now. I meant within the organization."
Apparently, the club is also considering calling up someone out of the rotation of Triple-A Indianapolis.
The leading prospect there would seem to be right-hander Brandon Cumpton, who is scheduled to start for the Indians on Wednesday. If he is pulled from that assignment, the Pirates' plans will become transparent.
Major League veteran Jeff Locke is out. He pitched for Indianapolis on Monday night.
Rodriguez's fill-in is not the only mystery surrounding the veteran lefty. The possible length of his absence is also an unknown.
While deferring to GM Neal Huntington, chiefly responsible for following up on injuries, Hurdle allowed that "knees can be different for different people."
Rodriguez had fluid drained from the knee on Monday, when he also underwent an MRI, results not yet shared.
"You can get a knee drained and have to get it drained again in two months," Hurdle said. "I know people who have had their knee drained a couple of times and had surgery in the winter. It depends on the guy. We'll just have to wait and see."
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. Teddy Cahill is a reporter for MLB.com. Follow him on Twitter at @tedcahill. This story was not subject to the approval of Major League Baseball or its clubs.