Anshakov had a broken hand and a neck injury after he was attacked in central Moscow Wednesday by a man wielding a crowbar, his group said.
Anshakov last fall accused Patriarch Kirill, head of the Orthodox Church, of "trading in the House of God," noting commercial activities, including a dry cleaner and a tire-changing service, at Moscow's Christ the Savior Cathedral.
He unsuccessfully requested the state prosecutor investigate what he considered inappropriate use of the cathedral, the Russian news agency RIA Novosti reported Wednesday.
The request led to a since-resolved libel suit by Vasily Poddevalin, head of the fund overseeing trade at the church. Monday, Poddevalin lodged another complaint in court against Anshakov, accusing him of embezzlement and fraud in connection with a charity for the disabled, the news agency said.