Caught stealing - How?

Lou Frazier (19 with his lead, 15 without) got caught stealing against catcher Rick Wilkins (-2) and pitcher Mike Torrez (+7). Isn't that a net +5 from the pitcher/catcher? How could Frazier be caught stealing?

Welcome to the game. Someone may come along with a shorter explanation but in the meantime here is a thorough explanation of what happens during a steal attempt. cummings2's post down the page a bit.

Help with Stealing Strategy

Here's the shorter reply: Odds to steal can never be better than 1-19 (i.e., there is always at least a 5 percent chance to get thrown out).

Same thing when you're trying to advance an extra base on a single or double.