Days of rest are FULL days of rest. If a player pitches their max on Saturday, they need 3 days of rest - Sunday, Monday, Tuesday. The pitcher would be able to pitch again on Wednesday.

A pitcher can go over their max pitch count ONLY if they are in the middle of a batter. If a pitcher in B pitches their 50th pitch to a batter who has 2 balls and 1 strike, that pitcher is allowed to finish the batter until the batter is either out or on base. After that batter, the pitcher must be retired.