When I say that, it's not so much about stolen bases as it is the ability to take an extra base, I like having more guys you can send home on a ball hit in the gap, etc. Base advancement has been studies to death. Dan Fox has done excellant work in that regard. He first came up with a metric he calls "Incremental runs", (IR) which tells you how much above average value (in terms of runs) a player adds from basepath advancement on hits. Here's the leader list from 2000 - 2004, in terms of IR: LINK Pierre is the best! Since then, he's come up with a more comprehensive approach at measuring speed on the basepaths (he writes for BP now, so I haven't followed his recent work very closely). It includes advancements on hits, outs and base stealing. Here's that list: LINK Pierre is still high on the list but he kills himself in base stealing attempts (-8.9 runs). According to Fox, the net run value above average of his speed on the basepaths from 2000-2005 is 18.5 runs. That's on average, worth about 2 wins over the course of 6 years. I stress average because he isn't looking at actual game situations, with regard to the outcome of of the games Pierre was in. Still, it gives us an idea of the magnitude of his base running value. Even if you trippled that number, it's pretty darn small.