The Riverside-based Harvest Christian Fellowship will be joining the Southern Baptist Convention, the nation’s largest Protestant body that has about 15 million members.

The Rev. Greg Laurie, pastor and founder of the 15,000-member Harvest, announced the move in June.

Some theologians see this as Laurie’s official shift toward mainstream evangelicalism and worry that Harvest could be overshadowed by the denomination. Laurie has been seen as one of the biggest crusaders of Calvary Chapel, an association of evangelical Christian churches to which Harvest belongs. Calvary was born as a movement away from religious denominations.

But, in a statement, Laurie calls the partnership an extension of the collaboration already taking place between Harvest and a network of evangelical churches that participate in the annual Harvest Crusades — a Southern California Christian institution that’s drawn millions of people to stadiums and arenas around the world. The SoCal Harvest event comes to Anaheim on Aug. 18-20.

“This decision does not change our theology, philosophy of ministry or our history,” Laurie’s statement said.

“It merely extends the reach of our fellowship within the Christian world at a time when the vision and mission of Harvest remains — as it has been for 42 years — focused on the teaching of God’s word and the preaching of the gospel of Jesus Christ.”

Laurie was not available for an interview last week, spokeswoman Laura McGowan said.

For Southern Baptist, which has been reported to be struggling with declining membership, this is a gain.

“We feel like it’s going to be a good move,” said Mike Ebert, a spokesman with the North American Mission Board, an organization supported by contributions of Southern Baptists. “He (Laurie) really will become a leader with the Southern Baptist Convention as a voice and an advocate for sharing the gospel.”

On June 11, the Southern Baptist North American Mission Board co-hosted with Laurie an evangelistic crusade at the University of Phoenix stadium in Glendale, Ariz. It attracted 38,000 people, according to The Baptist Press, the official news service of the Southern Baptist Convention.

Of those who attended, about 3,000 accepted Christ, while nearly 500 made salvation decisions online, The Baptist Press reported.

Ebert called it an example of what could be in store with Harvest’s new partnership. Laurie can help attract crowds, while Southern Baptist can provide resources to host such events, he said.

Some believe the merger could bring changes.

Southern Baptist and Harvest share many practices and beliefs in scripture, salvation, and evangelism, said Philip Clayton, professor of theology at Claremont School of Theology.

Any potential changes won’t be theological, he said.

Where Harvest and Southern Baptists differ is in their institutional structure, Clayton said.

“It is a big change for Harvest Christian Fellowship to be affiliated with a traditional denomination,” Clayton said. “There is the danger that Harvest Christian Fellowship will be completely absorbed by this massive denomination.”

“The Baptists are represented by the Convention, which speaks on behalf of a huge number of congregations. but up to this point, Greg Laurie has been the spokesperson for Harvest Christian Fellowship,” Clayton added. “That’s huge.”

Clayton said that in today’s religious landscape, it’s becoming harder for independent ministries to survive financially.

“We should see this merger as a symptom of a major trend in American evangelicalism,” Clayton said.

Read more at Rev. Greg Laurie’s Harvest Christian Fellowship merges with Southern Baptists.