"Before the transfer window opened five clubs were seriously interested in me. Two of the clubs were from Scotland and you can guess who they are," Boeteng told the Scottish Sun.
"I wanted to talk to these clubs but Southgate didn't allow it. I am very unhappy about this.
"The situation is difficult but my time at Middlesbrough is at an end.
"I am told both Glasgow clubs will come back for me this summer."