A 42

Blindness/deafness has only a verbal component, so I suspect you meant to ask about using Silent Spell rather than Still Spell.

And the answer is yes. Casting a 1-standard action spell is listed in the Combat section as provoking an attack of opportunity, and nothing in the rules for the Silent Spell feat changes that.

Explanation which includes a bit of extrapolation:
The act of casting the spell still requires you to spend a standard action, even if you don't need to speak. And during that standard action your attention isn't completely focused on what's around you. Because you're focused on casting your spell, you drop your guard ever so slightly, allowing the fighter to whack you upside the head.