Martin Whitmarsh has confirmed that McLaren won't be running a double DRS system in Belgium this weekend.
Mercedes introduced the device, which stalls the wing to cut down drag and increase top speed, earlier this season with their rivals quick to start work on their own versions of the device.
This weekend could see Lotus add their name to the list of those running a double DRS during a grand prix while McLaren, although developing their own system, are not there yet having instead opted to focus on other upgrades.
"It (the double DRS) hasn't received the maximum amount of resource because we have got a finite amount of resource, and we try and spend it where we get the biggest bang for the buck," Whitmarsh said during a Vodafone McLaren Mercedes phone-in.
"Our judgement so far is that we have been able to find other projects that deserve that resource and we can get a greater performance return from.
"There is no denying that the double DRS is interesting and I think there are other variants on it that have started to be seen on teams' cars, but they might not all follow a pattern that we saw on the Mercedes.
"We are not announcing when, where and if we are going to be introducing it. I think we will see different wing variants, certainly on our car along with a number of visual items as they go through scrutineering later today and hit the track on Friday.
"We will see new bits, but McLaren will not have a double DRS in Belgium."