They've changed the rules over the years. You used to be able to slide anywhere and put your spikes into the defenseless fielder. You used to be able to slide as late as you wanted, with no intention of getting to the base, but just to roll into the knees of the fielder. Now the rules (which I believe are very good) are you have to slide within an arm or leg length of the base and be able to stay on it...i.e. you can't slide late and go past the base, can't slide 5 feet wide of the base, etc....They did the rule change to protect the fielder. If you remember, that's how Biggio got his knee blown out in 2000, a roll slide into his knee on a DP at 2nd