This is outside my normal realm of analysis, but it's something I've wanted to address for a while. I'll get some Arizona Fall League Pitch F/x stuff up later in this week or early next week for sure.
I'm not too much of a pitcher, but I sometimes get that role in stickball games. I often struggle with my control. I'm inside, outside, high, and low. It really has nothing to do with my concentration or mental ability. It has a lot to do with my ability to throw a ball where I want to throw it.
If a quarterback misses on a throw, we don't accuse him of being a head-case. If a shooting gaurd misses a three, we don't accuse him of being a head-case. So what's my point here? Control is a skill, just like pitching velocity is a skill and pitch movement is a skill. An argument can be made that the control skill is in a way dependent on a pitcher's concentration, focus, and mental clarity, but then again, almost all skill actions in sports are.
We can acknowledge that pitchers like Manny Parra and also Yovani Gallardo have some problems with their control. It's not only measured by walks per inning but in general, better control sets up better success in getting strikeouts and groundballs-- the two best things a pitcher can do to help their success. But I don't think we need to assume that the control problems are the result of mental issues. It's not fair to the pitchers.
Concentration is an important part of athletics. The ability to concentrate is paired with a physical ability to make our world-class athletes what they are. A hitter must be able to swing a bat incredibly quickly, have fast reflexes and instincts, and be able to have the mental awareness and concentration to connect with a ball. In the same way, a pitcher needs to have the physical ability to throw a ball very hard, the ability to throw it where he wants to, and the concentration to not lapse in his mechanics and throw a poor pitch.
Pitchers are not in a unique situation that they can somehow become better by thinking harder and clearer. Pitching control is a skill. It's possible to improve control, just as it's possible to improve velocity or a hitter's swing. It's not fair to blame a pitcher's mentality or attitude for having less than stellar control unless we know something specific. It's not a logical way of looking at the problem when you compare pitchers to other types of athletes.
Criticism of pitch sequencing and selection is another issue entirely. Pitchers, catchers, and the coaching staff work together to come up with a plan before the game-- it's not as if a pitcher like Parra decides what to throw on the fly. If there are issues in this area, they need to begin changing with the coaching staff and catcher.