Both teams are expected to formerly announce the agreement Wednesday morning.
The relationship will allow LAFC to sign players and loan them to the Blues beginning this winter, a year before LAFC enters MLS. It also makes the Irvine-based Blues the 20th USL team to partner with an MLS team.
MLS clubs generally use their affiliates much the way major league baseball teams use their minor league partners: to give playing time to young, developing talent; to help rehab injured first-team players; and in some cases, to help players learn new positions.
But the deal between LAFC and the Blues could also be the first step toward a larger partnership. LAFC has not announced a location for its training facility although it has reportedly looked at sites in Orange County, where new Blues President James Keston is planning to build a facility of his own. Sharing that training site would make sense for both teams.
Keston, who took over as president in August, said the Blues, who played last season at UC Irvine, will also be changing their name as part of a rebranding effort.
Meanwhile construction on LAFC's Banc of California Stadium is expected to enter a new phase later this week with the first pouring of foundational concrete. The stadium will be the centerpiece of a $350-million complex next to the Coliseum in Exposition Park scheduled to open in March 2018.