Promoting supposedly high upside minor leaguers before they are dominating the minor leagues is a desperation move made by teams with no chance of post season play.
When Lewis is ready to play Rocco will have 1 lever to play, hopefully Castro can be super-sub instead of everyday Willie.
If the Twins are out of contention by the trade deadline they have very few tradeable assets that will bring a premium return, but they will need to be done for a reset.
The Twins are back to being Calvin Ball, hoping the drafted minor leaguers will develop and be better than the other teams draftees and free agents combined.