The experienced Northern Ireland international began training at Thorp Arch earlier this month, following his departure from Sheffield United, but Leeds have decided against adding another midfielder to the squad at Elland Road.
Simon Grayson said: "We've had a good look at him, it's the right thing to do when a player of his ilk becomes available. But we've decided that he's not going to get a contract with us because I feel we've got enough options in his position."
Meanwhile Australia international central defender Nikolai Topor-Stanley has returned to Newcastle Jets after an unsuccessful trial with the club.