Thompson was optioned to Triple-A Lehigh Valley on Wednesday.
Thompson made just two appearances (6.00 ERA across three innings) with the big club before being shipped back to Lehigh Valley. He'll likely see another chance with the Phillies this season, but the team wants to keep developing him as a starter, so he should spend the majority of his time at Triple-A until a spot in the Phillies' rotation opens up. A corresponding roster move should be announced prior to the weekend series against the Nationals.