He is essentially an opening batsman, but if the selection committee refuses to tinker with the Virender Sehwag-Gambhir combination, the 1 down is the only slot left for Vijay if he wants to play in the Test side.
He does have a Test score of 139 against Australia on home soil.
Virat Kohli: This would be a wild card. Kohli averages 47.5 in ODIs, but it comes down to 42.6 when he comes 1 down (which is still pretty decent). He is essentially a middle order batsman. But if he is up to the challenge, then why not?
He can try it out for the next home series and otherwise revert to his old position.