The lightweight showdown adds to the developing card, which takes place at the Staples Center on Aug. 2.
Castillo (17-6) has won three of his last four outings, most recently knocking out Charlie Brenneman at UFC 172 this past April. The finish was Castillo’s first win within the distance since 2011.
Ferguson (15-3) is the winner of two fights in a row, each of which was a finish. In his last outing, “El Cucuy” knocked out Katsunori Kikuno at UFC 173 in May.
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