Hang on, Laporte had the starting spot at the beginning of the season.
He didn't have to break into anything, he just had to play reasonably well next to one of the best central defenders on the planet, and he lost his place by making some really big mistakes and not performing - that's what let Stones in from the cold.
To want to leave after 6 months out of the starting lineup is incredibly weak if it's true. He doesn't even need to be better than Stones because Pep has said many times he prefers a left foot/right foot combination.