Tilson told Southend's official website: "I can't hide the fact I am disappointed he is going back as I felt we were getting there with the back four.
"But he is Swindon's player and it is their prerogative. I just hope they call him back for the right reasons and he plays because that is what the boy wants."
He added: "After Saturday we are going to be one light. Adam Barrett is our only recognised centre-back so we will see what we can do and get another one in."