There have been rumours in Italy that former Ferrari man Giorgio Ascanelli is being lined up to replace Whiting in the event that the long-time FIA technical head is forced to stand down over the row.
Red Bull team principal Christian Horner has also arrived at the FIA's headquarters in Place de la Concorde this morning for the hearing, accompanied by the team's chief engineer Paul Monaghan. It's not clear whether they are present purely as observers or whether they expect to provide any testimony to the hearing.
Red Bull originally raised the matter of the tyre tests with the FIA and have been leading calls for Mercedes to be heavily punished for their breach of the sporting regulations.
However there are fears that if the Tribunal imposes the most severe penalties for the infraction - which could even see Mercedes excluded from the championship - then the motor giant might decide to pull out of the sport altogether. The company's investment in developing the new 2014-specification V6 engine suggests that it a remote possibility, however.
Equally there is a big question mark over just what sanctions the Tribunal could possibly bring against Pirelli if the case against them was deemed to have been proven, given that the tyre manufacturer is not a competitor bound by the same sporting regulations as Mercedes but is instead working under a commercial contract.
And the Tribunal could be seen as just as crucial a test for FIA President Jean Todt, whose stewardship of the motorsports' top body has been seen as somewhat lacklustre since he took over from Max Mosely in 2009. A high profile controversial loss in the FIA's new appeals process would not be what the former Ferrari team principal needs ahead of his bid to win a second term in the post.