"It felt good," Chamberlain told The Associated Press. "Another step forward. That's all you can do."
Chamberlain dislocated his right ankle bouncing on a trampoline with his son on March 22. He has also resumed running sprints in the outfield and told the AP he will pitch this season.
"Is that even a question?" he said.
David Aardsma threw 40 pitches during his third batting-practice session and might be ready to pitch in a simulated game late next week. Aardsma is recovering from Tommy John surgery performed last July.