Super Aguri loses main sponsor?

It's only a whisper at the moment, but one of Narain Karthikeyan's 'options' might be to re-join the racing grid. Speculation suggests that Super Aguri's main sponsor, Japanese corporation Softbank, could have pulled out. The replacement? Again, it's only a whisper, but 'Tata' – Karthikeyan's major backer – has been mentioned.