The midfielder has joined the Championship club on a season-long loan deal.
The Yorkshire Evening Post had reported that as of Monday night, the Spaniard was still awaiting the international clearance he needed to finalise his move to Elland Road.
Leeds United manager Garry Monk
The 31-year-old had already agreed a season-long loan deal with the Whites, and the Yorkshire Evening Post claimed that United boss Garry Monk had intended to use the playmaker in their opening day contest with Queens Park Rangers.
However, the Yorkshire Evening Post added that the move was not ratified officially as the club continued to wait for the Qatari Football Association to submit the paperwork, leaving some doubt as to whether he would be available for the game at Highbury Stadium this week.
Hernandez during his time with Swansea
The news that Hernandez will be available will provide a major boost to the squad as they look to bounce back from their opening day humiliation at the hands of Queens Park Rangers.
Though Monk would have been confident that he had enough quality in his squad to handle a potentially tricky trip to face Uwe Rosler's side, having Hernandez available should allow the former Swansea man to get used to actually playing alongside his teammates ahead of their Championship clash with Birmingham this weekend.