The left-back was released by Chelsea on the final day of the January transfer window and later signed a one-month contract with Yeovil Town.
But the 22-year-old, who was twice sent on loan to Rugby Park by the Blues, has now agreed to return to the Scottish Premier League and is expected to pen a one-year deal with Derek Adams men on Thursday.
Gordon spent six months on loan with Killie in the second half of 2010, making 21 appearances.
The former Leeds youngster was also dispatched to Tranmere, Scunthorpe, Peterborough and Birmingham by Chelsea during a six-year spell with the Londoners after leaving Elland Road in 2007.
He then returned to Ayrshire in January 2012 and notched up a further 20 run outs for Kilmarnock, including a starting slot in the Scottish Communities League Cup final success over Celtic at Hampden.
Gordon will be County's third new arrival of the summer after the Dingwall side announced deals for Dutch wingers Darren Maatsen and Melvin De Leeuw.
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- Scottish Premier League