Grounds was expected to return at the end of next month but Boro boss Tony Mowbray told The Scotsman that Hibs may have an option to keep the 22-year-old in Edinburgh.
"There are financial implications to think about and I'll be assessing things in due course.
"In my mind I have a pretty good left-footed defender playing in the team at the moment. I have to give some thought on what's best for the squad and the team."
And Hibs manager Colin Calderwood said: "I've spoken to Tony Mowbray but it is something we have to leave until we get nearer the end of his loan, probably mid-way through January.
"It's not been decided one way or the other. First and foremost it will be their decision."