Well, this is a tough call, IMO.
Before yesterday, Leake really only had one bad start. I did not follow the game last night, but the box score says that he's a disaster.
Basically, everyone but Arroyo has been hurt or struggling this year.
That makes it a hard call for who should stay in the rotation.
IMO, this is why I liked the Arroyo extension. Maybe Arroyo doesn't earn his money in the last year of his deal, but he's earning it this year. Clearly the best pitcher so far. That might change by the end of the year, but he's by far the most reliable/predictable guy we have. He's the glue that holds the pitching staff together.