A sinker pitch can be used to trick batters in a few different ways. One is to use it as a changeup pitch, throwing it after a series of faster pitches to throw off the batter's timing. Another is to use it as a pitch that looks like it's coming in for a strike but then drops suddenly, causing the batter to swing over it. Additionally, a sinker can be used to induce ground balls and double plays, which can be advantageous for getting out of tough situations.