Definitely the most painful.
In the bottom of the seventh inning of Monday night's Diamondbacks-Reds game, Cincinnati second baseman Brandon Phillips was hit in the knee by a pitch.
Unfortunately, he swung before the ball hit him, so he was ruled out.
And then the same thing happened to Los Angeles shortstop Erick Aybar in the bottom of the eighth inning against the Cleveland Indians.
Like Phillips, Aybar was hit in the knee, but came around with his swing, so he was called out.