牵制球（Pick-off）为棒球战术之一；即投手将球投向有跑垒者之垒包，将其牵制。 一般情况，球员在上垒后都会站离垒包一段距离。这有助打击手将球打出后能更快跑到下一垒；另一方面亦能在有利情况下增加盗垒的成功率。因此，牵制球之主要目的为歇制跑垒者盗垒；在较少情形下更能将跑垒者点出（若跑垒者不能在牵制球抵达之先返回垒包）。

In baseball, a pickoff is an act by a pitcher, throwing a live ball to a fielder so that the fielder can tag out a baserunner who is either leading off or about to begin stealing the next base.

A pickoff attempt occurs when this throw is made in an attempt to make such an out or, more commonly, to "keep the runner close" by making it clear that the pitcher is aware and concerned with the runner's actions. A catcher may also attempt to throw runners out who likewise "stray too far" from their bases after a pitch; this can also be called a pickoff attempt. A runner who is picked off is said to have been caught napping, especially if he made no attempt to return to his base.