"We indeed informed both productions that Sean was not available now," Penn's representative, Mara Buxbaum, told E! News. "If for whatever reason the start dates on these productions were to be postponed, Sean would happily remain involved."
While no specific reason for the decision was disclosed, E! noted Penn and his wife, actress Robin Wright Penn, have split up and reconciled twice during the past 18 months.
The Penns are the parents of two teenagers.