This is what The Futon Critic informs:
As for "Revolution," Greenblatt made an off-handed remark during the executive session to "the last 10 episodes" of the season left to air. Said number would put the season total at 20 episodes, two shy of the traditional full season order of 22. A spokesperson subsequently confirmed to me that there are indeed 10 episodes left to air.
Source: The Futon Critic
