I don't think he'll be shutdown, but I think the Royals will be monitoring Greinke closely and will probably start to pull him earlier and earlier in games moving forward, as they'll obviously be out of it down the stretch. He's on pace for 245 innings this year, which would be a 40 inning spike, and he's admitted to some fatigue already. He was pulled at 100 pitches last night.
Again, I don't think he'll be shut down, because the Royals don't have a huge long term stake here (a free agent after 2010, I think), and he's really their only drawing card for attendance. But I wouldn't be shocked if they limited his innings.
Edit: Scratch the free agent bit. He's under control till 2012. All the more reason for the Royals to exercise caution.