Lewis Hamilton's unexpected positive COVID-19 test has thrown a spanner in Mercedes' works, but it is also set to deliver a potentially career-defining opportunity to one lucky driver.
Stoffel Vandoorne and Esteban Gutierrez are the Brackley squad's official reserve drivers.
The Belgian races for the German manufacturer in Formula E, but the former McLaren charger - as an active driver who is also virtually acquainted with Mercedes W11 thanks to his simulator work with the team - is also race-ready for a call up.
Vandoorne, who scored his first FE win last summer in Berlin, is currently testing with Mercedes' electric outfit in Valencia but is already due to travel to Bahrain once the test is completed.
Gutierrez's lack of recent running in F1, or in any other qualifying category, has deprived the Mexican of an F1 superlicence which effectively rules him out a substitute role.
British fans would lave to see George Russell get his hands on a Mercedes and so would many others in the paddock. However, there's no doubt that Williams would drive a hard bargain to release its young star, although in doing so it could reap a big marketing benefit if Russell later returns to Grove... a Grand Prix winner!
However, Williams needs Russell next weekend - and in Abu Dhabi - to try and improve its fortunes in the Constructors' championship and leapfrog Haas in the standings, a feat worth a few million dollars in prize money.
There also the question of who, should Williams release Russell to Mercedes, would replace the Briton? Reserve driver Jack Aitken could theoretically do the job.
Finally, Mercedes could rely on the trusty talent of F1 super-sub Nico Hulkenberg. The experienced German who replaced COVID-infected Sergio Perez and Lance Stroll at Racing Point earlier this season, fits the bill in all respects, and would enjoy the chance to finally add that elusive podium finish to his massive track record in F1.
But the fact that the Hulk is not acquainted with the mighty Mercedes team, contrary to Vandoorne and Russell, is an obvious disadvantage for Nico.