Hernandez has passed a medical and is set to be unveiled as Leeds’ seventh summer signing, arriving on a temporary basis from Qatari club Al-Arabi, writes Phil Hay in the Yorkshire Evening Post.
Al-Arabi signed Hernandez from Swansea City - a club where he played alongside Leeds’ head coach Garry Monk in 2014 - but he spent most of last season in La Liga on loan at Rayo Vallecano.
Monk sees Hernandez as a natural number 10 and the 31-year-old Spaniard will come to Elland Road with a view to a full-time move.
Leeds have already negotiated a deal to take Hernandez permanently in the January transfer window.
Hernandez began his career at Valencia and he became Swansea's record signing when he moved to Wales for £5.5m in 2012.
He is expected to train with United’s players for the first time on Tuesday and his addition to the squad has all but completed the work on the club’s forward line.
Leeds are continuing to pursue Sunderland midfielder Liam Bridcutt but are yet to make decisive progress with that transfer and the club remain in the market for a centre-back and a full-back.