I think your question can get a best answer only from Sachin Tendulkar himself. Because he plays for Indian team and not for himself. I think he will stop playing when he feels that he cant play well anymore due to his fitness. And only he knows about his fitness. So I dont find it usefull of talking about his presence in Indian team.
And hey this is my personal opinion, so dont take it very seriously.
With best regards,
a blog for electrical engineering students....