Alberto Del Rio appeared at a press conference at AAA's Ring & Rockstars and announced that he'll be teaming with La Parka and Myzteziz (aka the former Sin Cara) against Texano, Jr., Averno and El Hijo del Perro Arguayo in a tag team match on September 14th. Del Rio added that he has, with help from his lawyers and AAA, freed himself to wrestle for AAA without any difficulty.
As previously reported, Del Rio has a non-compete clause in place with WWE, though the details aren't clear. He may not be able to work in the US. You can see the press conference (which is in Spanish) below.