McLaren is still not committed to qualifying and racing with a Red Bull-style 'blown diffuser' exhaust layout.
At Silverstone, the British team tried the specification in Friday practice but reverted to the original setup for qualifying and the race.
McLaren and its drivers still head both world championships with more than half the season now run, but boss Martin Whitmarsh admits the team is "under no illusions" about Red Bull having the faster car.
He confirmed that the blown exhaust will be back on the car in Germany for a "major test programme" to compare the new and old floor layout.
"And, if these (tests) prove positive, we'll then look at the deployment of the new floor for the remainder of the race weekend. But that's a decision we'll only make after a thorough analysis of the inherent risks and benefits," added Whitmarsh.
It is expected that Sauber will also run a blown diffuser for the first time at Hockenheim.