Such is the concern over the Honda engine that McLaren have reported made "informal and brief" contact with Mercedes regarding an engine deal.
McLaren bid farewell to Mercedes power at the end of 2014, a year in which they finished fifth in the championship with two podium results.
Swapping to Honda engines in an exclusive deal, McLaren fell to ninth in 2015 before improving to sixth last season.
And although this year the team had hoped to take another step forward, they instead spent most of their pre-season stuck in the garage due to problems with their Honda power unit.
This has led to criticism from several McLaren personal with Racing Director Eric Boullier even stating that they "would" win races in 2017 if they were using Mercedes power.
And McLaren have reportedly spoken to Mercedes about renewing their relationship.
According to the BBC, 'McLaren's contact with Mercedes was characterised by sources as informal and brief and has not led to any resolution on either side. But the Mercedes board and motorsport boss Toto Wolff are said to be open-minded about the possibility of supplying their former partner.'
Meanwhile Motorsport.com reports that 'meetings have taken place since Barcelona testing to try to push Honda to take action needed to lift its engine programme, McLaren has not dismissed the idea of looking elsewhere.
'One avenue is the customer Mercedes engine supply that had originally been earmarked for the Manor team, and perhaps could be ready as early as later this season if Honda shows no signs of improving.'
McLaren, though, have refused to comment on the reports other than to say that they are "considering options" together with Honda.
"Winter testing was challenging and disappointing," a McLaren spokesperson told Sky Sports.
"We are working with Honda to address shortcomings and deficiencies. Together with Honda we are considering options, but we will not comment on media speculation."
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