Romain Grosjean's third place on the Hungarian Grand Prix grid is in doubt after his Lotus car failed a front floor deflection test on Saturday.
The Frenchman was the nearest challenger to front row men Lewis Hamilton and Sebastian Vettel at the Hungaroring.
But in post-qualifying inspections of the front floor, it was found that his E21 did not comply with the regulations.
A statement issued by the stewards said: "Car number 08 did not comply with Article 3.17.5 of the 2013 FIA Formula One Technical Regulations as the front floor deflected more than 5mm vertically when the load was applied vertically to it at the point which lies 100mm [from] of car centre line on the RHS."
Representatives of the Lotus team have been summoned to see the stewards to explain the situation - with a technical infringement likely to result in exclusion from qualifying.
FIA TECH REG ON FLOOR DEFLECTION
3.17.5 Bodywork may deflect no more than 5mm vertically when a 2000N load is applied vertically to it at three different points which lie on the car centre line and 100mm either side of it.
Each of these loads will be applied in an upward direction at a point 380mm rearward of the front wheel centre line using a 50mm diameter ram in the two outer locations and a 70mm diameter ram on the car centre line.
Stays or structures between the front of the bodywork lying on the reference plane and the survival cell may be present for this test, provided they are completely rigid and have no system or mechanism which allows non-linear deflection during any part of the test.
Furthermore, the bodywork being tested in this area may not include any component which is capable of allowing more than the permitted amount of deflection under the test load (including any linear deflection above the test load), such components could include, but are not limited to:
a) Joints, bearings pivots or any other form of articulation.
b) Dampers, hydraulics or any form of time dependent component or structure.
c) Buckling members or any component or design which may have any non-linear
d) Any parts which may systematically or routinely exhibit permanent deformation.