Is there any way?

[Dakota]

I agree with Mark. Especially with some pitchers, you really have no hope.

With other pitchers, though, if you suspect a runner is leaving early, you CAN help yourself out by making note of how the runner sets up on the bag (lead foot on the bag and trail foot behind the bag, or trail foot on the bag and lead foot ahead of the bag). This will tell you if she has to take one step or two to be off the bag. Then, watch the pitch, but keep the runner in your peripheral vision. You'll be able to tell if she is actually leaving early.

You still have to give the runner the benefit of the doubt (which you should anyay), but she does not have to be half way to the next base before you can call it.