Schuller, 86, fell last weekend at home in Orange and has been hospitalized since, the Los Angeles Times reported.
At the hospital, Schuller is undergoing tests and doctors may release him later this week.
"He's doing well, recovering quickly, and of course, our prayers are with him," said Angie Schuller, his granddaughter.
Crystal Cathedral Ministries is a congregation of the Reformed Church in America, founded in 1955 by Robert Schuller.
Schuller hosted a religious television show called "Hour of Power," which attracted more than 20 million viewers worldwide at its peak.
In 2010, the church filed for bankruptcy and the Roman Catholic Diocese of Orange bought the church's property in 2012, operating it as the Christ Cathedral campus.