The FIA has revealed that having met its requirements via its bidding process to become the sport's sole tyre supplier, the decision as to which of the companies wins the deal will be handled by the commercial rights holder.
Having withdrawn from F1 in 2006, still languishing under the dark cloud that was Indianapolis 2005, Michelin has been encouraged back to F1, most likely by the fact that the sport's governing body is run by countryman Jean Todt.
However, the French manufacturer only wants to return to F1 on its own terms, looking for less interference from the sport's powers-that-be and also seeking to change from the current 13 inch tyre to 18 inch, which, it says, will benefit the sport and tie-in with the tyres it already supplies to Formula E and WEC.
Pirelli, which is understood to be Ecclestone's preferred option, insists 18 inch tyres would not benefit the sport – a claim supported by many within the paddock including Paddy Lowe - and would in fact drive up costs as suspension systems and brakes would need to be redesigned.
Whilst far more malleable, in terms of supplying rubber to suit Ecclestone's demands in terms of the racing, Pirelli, which returned to the sport in 2011, also spends a lot of money on trackside advertising, unlike its French rivals.
A decision is expected later this year after Ecclestone has discussed the situation with the sport's controlling shareholders and then put before the FIA's World Motor Sport Council for approval.
On the other hand, many fans and drivers would like to see a tyre war, feeling that it adds to the 'spice'.
Check out our Thursday gallery, here.