A source close to the presidential campaign of Rick Santorum tells ABC News that the former Pennsylvania senator will pick up the endorsement of Christian conservative activist Gary Bauer on Sunday.

Bauer ran for president himself in 2000, and is part of the group of conservative leaders trying to figure out around which candidate the movement should coalesce so as to stop Mitt Romney from grabbing plurality wins all the way to the nomination, with conservatives like Santorum, Newt Gingrich, Rick Perry and Ron Paul splitting the non-Romney vote.

The news of Bauer's endorsement was first reported by the Washington Post's Dan Balz.