Reader Jim sends along this question:

CC Sabathia was constantly going to his forehead and wiping the sweat. Home team TV coverage kept cutting away right after he moistened his fingers, so I never saw him wipe it off. What’s the rule these days about going to the mouth/forehead while on the mound? He was always right near the rubber when he did it.

Well, a quick check of the rulebook shows that nothing in particular is mentioned about pitchers and sweat.  It is very specific about pitchers going to the lips or mouth, but no mention of sweat.  There are some stipulations about “foreign substances”, but possibly sweat is not considered foreign?  Unfortunatley, the interweb doesn’t offer up much of an explanation as to why this is not included in the rules.  All I can say is that it must not be that big of a deal.  Also, it seems that most of the discussion centers around foreign substances such as dirt or rosin on the ball.  Sweat must not make that much of a difference.