McLaren sporting director Sam Michael believes Formula One's pecking order will be mixed up at the start of 2014 as the rule changes could lead to reliability problems.
The sport will switch from the current 2.4-litre engines to the 1.6-litre turbocharged V6s next year while teams will also use more energy recovery systems.
With so many changes, most of the teams have already shifted their focus to development of their 2014 cars as they look to get an edge over their rivals.
Michael believes it could lead to a bit of shake-up in the grid at the start of the season.
"When you get a big rule change the engineering structures are not fast enough to respond, even if you're given two or three years to design cars for 2014," he said during a Vodafone McLaren Mercedes phone-in.
"Although we're a world away from where we were 20 years ago in terms of preparation, ultimately until you get out there and run properly you're not going to have as much reliability as you do on the current cars.
"So do I think it will mix things up? Probably. There'll be different results that wouldn't occur like they do now. It's just another thing that's part of rule changes and it's something that you have to cope with."
Michael warns that teams run the risk of pushing too hard and being left with cars that are unreliable.
He added: "When you've have such a big change to the powertrain from a mechanical side, you will build in more margin than what you would have done previously.
"Let's say we hadn't made any changes to the powertrain for next year; what you'd be doing is taking an extremely well-known product and chipping away at marginal gains - a little bit of weight here, a bit of friction there, maybe a change in packaging.
"That's all gone out of the window for 2014 and you'll be in one of two positions - either you've pushed it too far and you'll be unreliable or you'll be too heavy and you'll want to take some weight out of the car. Both of those things take time. You won't have got it bang on in all areas of the car, so everyone will be in the same game."