Lowe has been strongly linked with a switch to Mercedes as part of the German outfit's management restructuring.
During the launch of the 2013 McLaren Formula 1 car, Whitmarsh insisted Lowe was still on board.
"One certainty is that Paddy will be part of the team for another year," Whitmarsh said. "It's less certain beyond that.
"That is something that we will have some certainty on in the near future."
Asked about Lowe's absence from the launch event, Whitmarsh said his technical chief had chosen to stay away given the media coverage of his future.
"Clearly there is a lot of media interest and I think it is good that Paddy concentrates on doing his job," said Whitmarsh.
"I don't think he wants to create embarrassment to his team or his colleagues, so on his own election he felt it not appropriate to be here."