This is getting close. India need to play slightly restrainingly, to ensure that they don't lose the match in going for a win. This is exactly the situation England would have wanted, except with perhaps a few more runs on the board and a few more overs to bowl at the Indians.
Kumble coming up the order means that we lose his 'sticking' value down the order. Another problem is that both Jaffer and Kumble are grafters. We do not want to be controlled by the bowling, like England were.
From what I understand, the surgery on Tendulkar's shoulder will keep him out of cricket for 2 months. It will probably take those 2 months to make sure the surgery has worked and that he is recuperating properly. As such, the injury is probably one that won't affect him too much, but will be problematic in the long-run if it is ignored for too long. India have many back-to-back tours, and this was probably the best time to do it.