Monisha Kaltenborn fears Sauber could have a "very tough" time scoring in 2016 as Manor swaps to Mercedes power and Haas joins the grid.
Although Manor has been lapping at the back of the field since entering F1, the team is expected to make massive strides forward next season.
Not only have they secured Mercedes power but the team has also entered a technical partnership with Williams.
Manor, though, won't be the only new outfit joining the points battle in 2016 as Haas are also expected to be up there.
Gene Haas' American team has Ferrari power and a technical relationship with the Scuderia leaving many to predict that top ten finishes could be on the cards.
And for everyone that Manor or Haas secure, that's one less for Sauber.
"I am, in principle, happy because we have, in many ways, come back to where we usually are, but I think there is more potential there which we have to utilise next year, so I'm not totally happy," Crash.net quotes Kaltenborn as having said.
"We have Manor coming in with a new [engine] tie-up, and we have a new team coming in which, we learned from the media, has had intensive co-operation with another team, so it's going to be very tough to score a point.
"I think you'll really have to do that on your own because a lot will have to go wrong [for others] for you to be there and score a point."