McGregor has been undergoing medical tests in
The 30-year-old has been looking for a new club after leaving Rangers when it was consigned to liquidation.
The Rangers newco, who McGregor declined to join, will dispute his right to move but the goalkeeper's former team-mates who followed the same route have been granted temporary transfer certificates by FIFA ahead of arbitration over possible compensation.
Like Rangers, Besiktas failed to meet financial criteria to gain a UEFA licence and could not take its place in this season's Europa League.
Newcastle Jets have been crowned Champions of the Singapore Soccer Sixes after defeating Chonburi FC of Thailand 4-1 in Sunday’s grand final.