McAllister met the Fratton Park based club but failed to agree terms and Portsmouth manager Paul Hart told BBC Radio Solent: "Gary won't be coming. We've failed to reach an agreement. I'm disappointed but that's the way the cookie crumbles."
McAllister has also been linked with a role at Northampton Town but if he cannot agree terms with a Premier League club, it is unlikely that a League Two club would be in a position to better what Portsmouth and the Scottish National team offered him.