But in the following hours, Marussia issued a press statement announcing that the well-backed Briton Max Chilton is staying put for a second season.
"Continuity is important for the team but also for me as a driver," he was quoted as saying.
And reports the Marussia 'asterisk' was a sign of uncertainty were also denied by team president Graeme Lowdon at the Autosport show in Birmingham.
He also said the intention is for the team's 2014 car to make its test debut at Jerez late this month.
"With our race driver lineup complete we can now focus all of our attention on our 2014 car and moving Marussia to the next level," said team boss John Booth.
At the same time, the signals from Lotus - similarly conditional on the FIA entry list - are not quite as bright.
But Italy's Omnicorse speculates that the problem may simply be the fact that the legality of the Enstone team's nose solution for its 2014 car may have been rejected by the FIA.
And the Finnish broadcaster MTV3 suggests that the missing link could be the dotted line on a new Renault engine deal for the black and gold team.
At any rate, Lotus continues to work hard on its 2014 car, with the team's official Twitter revealing a teaser preview of the E22.
"Seeing is believing," the Twitter message read last week. "Hello E22, and oh how you're growing."
Finland's Turun Sanomat newspaper, however, said its investigation found that Lotus will probably be the only team missing in action at the Jerez test.
"Only Marussia's plans are not certain," said correspondent Heikki Kulta.
Lotus team boss Eric Boullier insists there is no cause for concern.
"Everything is fine here," he told the BBC. "Lotus will be on the grid this year and for a long time."