The 26 year old goalkeeper has been capped 26 times for Serbia but has fallen out of favour at Sporting Lisbon.
He has spent much of last season on loan with Getafe in La Liga, but has yet to play so far this season.
Ironically, Stojkovic could come face to face with Kingson in the summer as both Serbia and Ghana have been drawn in the same group.
It is not even January yet and perhaps the Stojkovic addition could be the first of many next month.