BEIJING — Chinese Communist Party officials have put an outspoken property tycoon who is a party member on a one-year probation for writing online comments criticizing President Xi Jinping’s propaganda policies, according to reports published on Monday by Chinese news websites.

The probation means the tycoon, Ren Zhiqiang, could be expelled from the party, which has more than 85 million members, if he steps out of line again. The news was announced on a public holiday by party discipline officials in the Xicheng district of Beijing, a sign that the party wanted to get the news out quietly, perhaps because of Mr. Ren’s popular online presence.

Mr. Ren wrote comments on his microblog in February questioning a major announcement that month by Mr. Xi that Chinese news organizations must serve the party. Mr. Ren wrote on his main microblog, which had nearly 38 million followers, that the Chinese news media should serve the people and not the party.

Mr. Ren had a reputation for posting contentious statements, which earned him the nickname “the Cannon.” Censors quickly deleted his posts on Mr. Xi’s new policy, and a website managed by the Beijing party committee’s propaganda bureau said Mr. Ren had “lost his party spirit” and taken up “opposing the party.”