According to Marlins.com this is order of the starting pitchers for the "second half":
Ricky Nolasco, Josh Johnson, Alex Sanabia, Anibal Sanchez and Nate Robertson.
Since JJ pitched two innings in the All-Star game, the Marlins will pitch him number two. This was expected, and anyway, it really doesn't matter; he will get the same amount of starts as if he didn't. Plus, the fact that Ricky is starting to be Ricky means there should be no loss in quality.
Sanabia didn't magically vault himself to number three starter by pitching 3.1 innings and leaving the game with the bases loaded only to have Burke Badenhop bail him out. I suspect the reason is the club does not want him and Nate following one another since there are only so many middle relief pitchers on the squad. Having them back-to-back would really over tax the bullpen.
Also, Sanabia may not be long for the rotation. I expect at some point Chris Volstad will return, not to mention that Alex is behind Sean West and Rick VandenHurk when it comes to ready-for-the-majors starters. In the meantime, it does give the organization a chance to see how far the young Mr. Sanabia has progressed.
Has the towel been thrown into the ring? Time will tell. But right now it appears so with the talk of Emilio Bonifacio leading off and Sanabia still being in the rotation. However, sometimes looks are deceiving.