"There's light," Chamberlain said. "I see a little bit. It's peeking through."
Chamberlain threw a 45-pitch bullpen session on Thursday morning prior to the Yankees' afternoon matchup against the Red Sox, and he said his arm strength has continued to progress with each step of his rehab.
"Just getting my arm going, it felt better," he said. "As we continue to do this thing, it seems to get stronger."
The 22-year-old righty has been on the DL since he took an early exit from his Aug. 4 start in Arlington with right rotator cuff tendinitis. Chamberlain has worked through a program with head trainer Gene Monahan to build his way back, increasing the number of pitches and their velocity as the process continues. He said he has gone through all his throws, and his slider in particular felt improved on Thursday.
Chamberlain will throw 35 pitches to hitters at batting practice on Saturday to create a more game-like situation. He said he will likely make the first 25 pitches to simulate an inning, sit and then throw the remainder.
A screen is typically used to protect pitchers during BP, and even though Chamberlain said he expects there will at least be a cage on Saturday, he will ask to pitch without the screen.
"I don't like screens if I'm trying to get used to a game," Chamberlain said, though he was not sure the team would honor his request.
If he continues to feel good after throwing on Saturday, Chamberlain said he feels he would be ready to go in a game as early as next week. In that timetable, he would return directly to the Major League club without any Minor League rehab assignments.
But the capacity in which Chamberlain will perform for the Yankees is still uncertain. He said with the rehab program he has gone through, he is doubtful that his first return appearance would be as a starter. General manager Brian Cashman said it's a topic that has been given thought, but he would not make any decision until Chamberlain completed batting practice on Saturday.
"That's a discussion we have to have, if there's enough time to stretch him out as a starter," Cashman said.
Physically, Chamberlain is no longer concerned with his injury. His primary concentration at this point is improving his location and getting back to the big leagues to help the Yankees make a final postseason push.
"You've just got to get out there and let it fly," Chamberlain said. "You've got to get in here and try to help this team win as much as you can. You can't really worry about [the injury] -- and then just try to focus on hitting your spots as much as you can."
Samantha Newman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.