Romain Grosjean says a final decision on whether Lotus gives its double DRS a race debut in Belgium is unlikely to be taken until after Saturday morning practice.
Lotus was thought likely to use the device in a grand prix for the first time at Spa.
- the circuit where it is expected to be most beneficial - but Friday's heavy rain meant there was little chance to evaluate it.
"We will see what we can do tomorrow," said Grosjean. "I don't know what is decided yet, if we keep it on both cars or only one car.
"For sure it was not the best conditions and we needed some dry weather to see if it was working as expected, but tomorrow we'll maybe keep it for P3 and then we take the decision."
When asked if it would be straightforward to remove double DRS between final practice and qualifying, Grosjean replied: "I think it will be hard work for the mechanics, but we should be able to achieve it."
Grosjean was ambivalent about whether Lotus decided to run the system at Spa or not.
"I think the best decision has to be taken by the engineers, but honestly on my side it is the same if I use it or not," said Grosjean.
"Hopefully the performance is good without the upgrade and we'll have an easy solution.
"Nobody knows where we are. Let's see tomorrow in P3.
"It will be a hard work session but by then we should know a bit more about performance and if we want to take a risk or not."