Mark Webber admits fellow Australian Daniel Ricciardo's move to Renault is a "concern".
Also a former Red Bull driver, Webber says Ricciardo's decision to leave the energy drink team for the French works outfit could be "an inspired decision".
"We'll all have to sit back and watch, but the move is under a little bit of heat. It has to work for him," Webber told Fairfax Media.
"He knows in the short term it's going to be (a step back). He'll be behind Red Bull next year. He's banking on the long term there. That's the concern."
However, Webber acknowledges that in formula one, sometimes it's necessary to take a risk.
"That's what you've got to do sometimes, you've got to be one step back, two steps forward," he said.
"He's got a lot of time left but we all would like to see him in a more competitive situation than he's going to be in over the next two years," added Webber.