This is a baseball phrase used to describe a style of hitting illustrated by lots of pitches, and walks, but few swings. This type of hitter will typically wait for a specific type of pitch, or a pitch in a particular location. This style of hitting may also be used to combat a pitcher whose time between delivering pitches is too fast for the batter, or simply to throw of the pitcher's timing. Typically, a patient hitter will never swing on the first pitch. The length of at-bats for patient hitters is generally longer, on average, than a typically hitter who swings when they see a good pitch.
A hitter capable of being patient is valuable to at a team because they help wear down the pitcher and are usually much more efficient at the plate. This is because they will usually get the pitch they are waiting for, get a walk, or force the pitcher to strike them out, which will take at least three pitches. A patient hitter has become a much more valuable commodity recently. Team executives have begun to understand the true value these players have based on how many runs they are capable of producing.