“During the event Ott caused damage to one of his allotted rear differentials. Withdrawing Ott from the event was a big decision and a big sacrifice but it means that we can now seal new transmissions for the remainder of the link without incurring a penalty as described in the WRC regulations.
“Under the regulations we could have still finished the event with Ott and claimed a new transmission set by using a ‘joker’, however due to the number of events remaining this year we have decided to keep this option should we need it at a later date when a driver of the M-Sport Ford World Rally Team is in a higher position.”
World Rally Championship - News - Tanak's Germany withdrawal explained