变化球是棒球中的一种球路，它不像快速球，会产生各种不同方向或速度上的变化。曲球、弹指曲球、滑球、滑曲球、螺旋球都是变化球。

In baseball, a breaking ball is a pitch that does not travel straight as it approaches the batter; it will have sideways or downward motion on it, sometimes both (see slider). A breaking ball is not a specific pitch by that name, but is any pitch that "breaks", such as a curveball, slider, or cutter—also known as a cut fastball. A pitcher who primarily uses breaking ball pitches is often referred to as a junkballer.[citation needed]