Manager Joe Girardi said that Chamberlain would be on track to throw 50-55 pitches when the Yankees meet the Orioles in the series finale of a three-game set at Orioles Park. Girardi acknowledged that his rising pitch count may require a start the next time through.
"It could be, but we'll see," Girardi said.
Not wanting to option Chamberlain to the Minor Leagues while they convert him into a starting pitcher, the Yankees are plotting Chamberlain to continue increasing his pitch count at the big league level, while also working toward an eventual goal of about 100 offerings.
Chamberlain made his 19th appearance of the season in the Yankees' 12-6 victory over the Mariners on Saturday in New York, throwing two scoreless innings and a career-high 40 pitches.
Left-hander Andy Pettitte is set to start against the Orioles on Wednesday, and Girardi said that he would not cut short Pettitte's outing just to get Chamberlain in, especially with an off-day on Thursday. The Yankees open a series in Minnesota on Friday.
"We'll see how the game is going with Andy," Girardi said. "If it's not Wednesday, it may have to wait until Friday."
Girardi said that he has been satisfied with the level of communication from Chamberlain, who signed off on the decision to transition to the starting rotation last week in New York.
"It's the same as any other pitcher," Girardi said. "Just let us know how you feel. If your legs are fatigued or your arm feels a little fatigued or whatever it is, you've got to just let us know."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.