IMO the only reason they couldn't touch him is because they got themselves out.
When they face him again, they need to be much more disciplined and force him to throw actual strikes. They swung at so much of his junk pitches that it was easy for him. As Smoltz said, pitchers are happy to face undisciplined hitters because pitchers do not need to throw strikes to get them out.
The current lineup may not have that ability unfortunately with hitters like Hoskins, Marsh, Castellanos etc., but getting him into hitters counts where he has to throw his FB instead of the curve is key. It is like facing Lefty (I'm not at all saying Valdez is anywhere near as great as Lefty). If Lefty got two strikes on you, you knew the slider was coming and still could not lay off it. With Valdez, you know the curve is coming with two strikes and you need to learn how to let it go by.