John Patterson went to a doctor in Cincinnati on Monday to have his back, which had grown sore after his last start, checked out. Esteban Loaiza woke up Tuesday morning, his neck as stiff as it has been in a week. So the Washington Nationals went to bed Tuesday night unsure of who would start Wednesday against the Pittsburgh Pirates.

"It's up in the air," Manager Frank Robinson said. "Sleepless night. Try to figure out what I'll do if neither of them can go tomorrow."

The only other candidate is Sun Woo Kim, who threw 87 pitches at Texas on Sunday before coming up with a forearm cramp after 42/3 innings.

Loaiza already skipped his original turn on Sunday, and was going to be pushed back to Saturday had Patterson been ready. Loaiza wore a heated neck brace in the clubhouse Tuesday.

Patterson, though still sore from injections in his back, played catch Tuesday, and said he would be ready.

"I'm coming here prepared to pitch tomorrow," he said. "I don't think anything will hold me back from pitching tomorrow."

Eyes on Castilla, Cordero

Vinny Castilla and Wil Cordero, who are slumping badly, took early batting practice under the eye of Robinson, General Manager Jim Bowden and hitting coach Tom McCraw. Castilla was hitting .164 over his previous 15 games, Cordero is 1 for 25.