George, 25, will now be able to turn out for Rovers at the Magic Weekend against Hull.
Giants managing director Richard Thewlis said: “Luke is in the team across on Humberside and they must be happy with him as they wished to retain him for longer which is great news.
“RFL regulations mean that after a month the arrangement can be revoked by either party at a days notice so the natural thing is to continue as we are.
“Clubs situations can change quickly as we all know injury and form wise and as we are relatively healthy in the outside backs I think it’s another win win for all concerned that he remains representing the Robins for now.”
George has played three times for Hull KR, against Leeds, Castleford and Wakefield.