As things stand, there is presently only one Japanese driver set to line up on the starting grid for the Bahrain Grand Prix F1 2010 curtain-raiser in Sakhir in just over two months' time - but that figure could be trebled should paddock speculation prove to be on the money.

Having impressed so greatly on his two end-of-season appearances for Toyota last year, Kamui Kobayashi has been snapped up by Sauber for the forthcoming campaign, and now authoritative French publication Auto Hebdo reports that ex-Super Aguri ace Takuma Sato has entered the frame to partner Robert Kubica at Renault, under new ownership following the majority 75 per cent sale of its Enstone-based F1 operation to Luxembourg investment firm Genii Capital.

It is understood that Sato - due to turn 33 later this month - is on a five-strong shortlist that has been compiled by new Renault F1 team principal Eric Boullier, alongside experienced BMW refugee Nick Heidfeld, Romain Grosjean, J?r?me d'Ambrosio and Ho-Pin Tung.

Grosjean competed for Renault over the second half of 2009 following Nelsinho Piquet's sacking, whilst both d'Ambrosio and Pin-Tung are members of the Gravity Sport Management programme, which has close links with Genii Capital and was until recently run by Boullier. Young Chinese hopeful Pin-Tung tested for Renault at Jerez last month, whilst GP2 Series star d'Ambrosio has insisted he is not ready for F1 - yet [see separate story - click here].

Sato last raced at the highest level in the 2008 Spanish Grand Prix at Barcelona prior to Super Aguri's financial collapse, and from his 90 grand prix starts to-date has a best finish of third place for BAR-Honda achieved in the 2004 US Grand Prix at Indianapolis, behind the all-dominant Ferrari pairing of Michael Schumacher and Rubens Barrichello.

"We haven't given up," his agent Matthew Winter has insisted. "There are still a few seats open, and we are trying to hunt them down. His options are running out, so we don't know if he is going to be in F1 next year."

Meanwhile, it seems compatriot Kazuki Nakajima - who most assumed had come to the end of the road in F1 after consistently underwhelming in 2009, failing to score so much as a single point as Williams team-mate Nico Rosberg tallied 34.5 - could be handed a lifeline to extend his career on the grand prix grid, should 2010 newcomer Campos Meta 1 fail to make it.

It has been reported in recent days that the Spanish outfit is struggling to reach its required budget and pay its bills ahead of the new campaign, and that it is consequently looking for a buyer. According to Finnish newspaper Turun Sanomat, the favoured option of the sport's influential commercial rights-holder Bernie Ecclestone is Serbian concern Stefan GP, which has already agreed terms with Toyota to purchase the rights to its ready-designed TF110 chassis, gearbox and engine following the Japanese manufacturer's withdrawal from competition.

Stefan GP has made no secret of its desire to join the field this season, and it is believed that should it be successful, the long-time Toyota-supported Nakajima would come as part of the package, alongside former GP2 Series runner-up Bruno Senna, who was confirmed as one of the two drivers at Campos before Christmas.