Martin Whitmarsh maintains McLaren will 'look at anything' - even last year's car - if they cannot find a solution to this year's problems.
Having had one of the strongest cars in the latter stages of last year's Championship, McLaren had hoped for a flying start to this campaign. That, though, was not to be.
The Woking team struggled for pace in the season-opening Australian GP where Jenson Button finished a distant ninth while Sergio Perez was not even in the points.
McLaren's misery raised the question about whether they would consider reverting to last year's MP4-28 with Whitmarsh admitting it could be a solution.
"Well, not before next weekend that is for sure," the McLaren team boss told Sky Sports F1 when asked if reverting to the MP4-27 was a possibility.
"We will see, we are not too proud to say when we get things wrong, and we do occasionally.
"But for the time being we have to try and get some understanding and do the best job we can do go forward with this car as quickly as we can.
"It probably won't be as quick as I'd like or many people would like but we think we can work this one out, but if we can't we will look at anything."
Whitmarsh admitted that McLaren's back-to-back Aussie triumphs in 2011 and 2012 added to the team's suffering on Sunday.
"It has been a weekend where we have had to force a smile a few times - it has been tough. It is tough to start a year like this, you make decisions during the winter and sometimes they don't come off and it is not pleasant being here if you are used to being a front runner.
"We won the previous two grands prix and to be here with a lack of pace and frankly not understanding the car and really struggling made it difficult for the team."
The Brit, though, was impressed with how his drivers handled themselves in the face of adversity.
"The drivers did a great job this weekend as it is very easy to let your head drop - we went into the race with Jenson in the worst possible shape with heavily-grained tyres and he had to stop very soon so to come through and score some points was good for him.
"For Sergio to come from 16th and nearly get into the points is a solid job. We didn't have the pace so we had to rely on the drivers doing a great job looking after the tyres and doing the best job they could."