I think Natarajan is now fit to play T20 and ODI matches for the Indian national team. Now he is in good form. The Indian coach should now collaborate to further develop Natarajan’s talent and skill. Otherwise, Natarajan will not be able to service the India team for a long time. He will be lost in the crowd of other players. We have seen before that many good talented players are lost due to lack of perfect direction.
To play IPL for a month and now playing in Australia and performing you think Natarajan has fitness issues 
. The talents that did not fulfill is because they did not change with the demands of international cricket and you need to evolve as a cricketer because the opposition team is always learning your bowling skills and until you evolve and change you will fade out.