I was reading a question on what it is like inside of a Poké Ball. It made me wonder what will happen to a Pokémon if the Poké Ball is lost or damaged. If the Poké Ball was unable to open, would they simple die?
There have been several instances in the show where a Pokémon was in its Poké Ball for a long time, such as in Sandshrew's Locker. In this episode, Ash and friends helped Mira recover Sandshrew's Poké Ball from the bottom of the lake, where it's been for a long time. Additionally, Mira and her friends discovered Sandshrew's Poké Ball themselves. In the episode Two Degrees of Separation! James found his Carnivine's Poké Ball inside a box containing one of his bottle cap collections, where he left it as a child. So, the precedents in the show indicate that Pokémon can survive a long time unattended in their Poké Ball, though it is unclear as to why since how the Pokéballs work is not well explained.