Liverpool goalkeeper Pepe Reina would welcome a return to Barcelona next summer.
Sheffield Wednesday chairman Milan Mandaric has confirmed Neil Warnock is on a five-man manager's shortlist.
Brittain, 29, agreed a pre-contract with St Johnstone in January but changed his mind and decided he wanted to remain with County for "personal reasons".
He also reportedly signed a new deal with Ross and the two clubs have been locked in a tug-of-war over the player, which has now been resolved.
A statement from St Johnstone read: "Following a meeting between our chairman Steve Brown and his opposite number at Ross County, St Johnstone FC wishes to announce that an agreement has been reached, on terms that are acceptable to St Johnstone, for the cancellation of the Scottish Premier League contract between St Johnstone FC and the player Richard Brittain."