Harris will almost certainly be farmed out in January for two main reasons:
1) OUFC will look to upgrade in that area, from a guy that hasn't found the net for 8 months.
2) If Wales secure a play-off place for the World Cup, Harris will need to be playing football you'd imagine, to be in contention for a place in the squad for the play-offs in March and WC in the Summer (if they qualify).
Based on current form and minutes played, who on earth is going to take Mark Harris on a permanent basis in January, when you consider the bloke has not scored for months? No, it will almost certainly be OUFC subsidising a loan move that suits Harris for the second half of the season, and it will then be a summer of touting him around to potential suitors that would be willing to take him on a permanent deal, on terms that get somewhere near the substantial salary that we are paying him.
Was it a mistake to offer Harris a new deal, off the back of him scoring 6 goals in 46 games last season? Absolutely, and it may come back to cost us for some time yet. See Stuart Findlay for comparable evidence.