Pirelli will have to send Nico new undies for Christmas! Mercedes was not amused.
Pirelli later explained with an "oops, our bad":
"PIRELLI: MERCEDES FITTED WITH PROTOTYPE TYRES WHICH WILL NOT BE PROPOSED AGAIN. 2014 DEVELOPMENT GOING ACCORDING TO PLAN
Milan, 19 December 2013 – The tyre tests in Barhain regarded a number of prototypes, which were completely innovative in terms of structure and compounds, with the aim of developing the most suitable solutions for the next season.
This morning Nico Rosberg’s Mercedes was fitted with one of these prototypes, a tyre which had only been tested in the laboratory and which will not be proposed again.
Thus, the safety of the tyres which will be supplied for the next Championship is not in question.
The accident which happened to Rosberg’s car is being investigated and the findings will be communicated to the FIA and the teams."