Forster's performances for Celtic have helped establish himself in Roy Hodgson's England squad, and after his club's early exit from Europe, the former Newcastle United stopper has admitted that he doesn't know where he will be playing during the next campaign.
The 25-year-old told STV Sport: "I don't know. There's a lot of time between now and then. It is hard to say either way. Obviously I'm contracted to Celtic and I will be for the foreseeable future I imagine.
"It is just important that I do the best that I can, whether it is for Celtic or whoever.
"I've just got to be positive and do everything that I can between now and the end of the season to try to force my way on to the plane with the England squad."
Forster has made 176 appearances since moving to Scotland in 2010.