You can't stop him, you can only hope to contain him: Michael Bourn has been a terror on the basepaths in 2009. More important than his 52 stolen bases is how he's stealing them. His ten caught-stealings this season is equal to his 2008 number, but he has already surpassed his 41 total stolen bases from 2008 by a wide margin. A 84% success rate is nothing to sneeze at and this represents yet another aspect of his game that Bourn has improved upon.
While Michael has been praised mostly for his strong batting numbers, his already superb base running game is getting better and better as well. You can look at Fangraphs and see that his SPEED score is 8.5 this season as compared to 7.3 in 2008. I don't know how well that number translates into on field performance though. Wrapping your mind around it seems tough.
Baseball Prospectus' base running stats are actually a little more palatable in this regard (though in most cases, BPro doesn't tickle my fancy). It's EQBRR (Equivalent Base Running Runs) paints a better picture of his effect not only on the bases, but on the Astros' bottom line. On their stats page, each component of base running is laid out in a line, making it easy to compare players across the spectrum. So, if you wanted to compare Mike to another player you can look down the line and see how well he compares to the other great base runners.
I've made this comparison before, but Bourn is only outdone in terms of stealing bases by one player- Jacoby Ellsbury. Even then, the difference is negligible and isn't worth discussing. If Bourn is the best base runner in the game, you would expect Jacoby to be close behind. He is in the top ten, but just barely at number nine overall, behind the likes of Ryan Zimmerman and Chase Utley. Obviously stealing bases contributes a great deal to your overall base running production, but it isn't everything. Players with lesser speed like Utley and Zimm outpace Ellsbury in advancing on outs (both in the air and on the ground) and taking the extra base. Michael Bourn, on the other hand, is across the board in the top tier of all base runners. It should be no surprise then that not only is Mike the best in MLB, but he is almost a full win better:
In other words, Bourn is 13 base running runs above what would be expected of a replacement player in a park adjusted environment. That's a tidy 1.3 wins that he's added to the Astros' total this season. It's only a portion of his overall value, but considering how tough it is to make a noticeable difference on the bases, Bourn has done so, and has separated himself from the rest of MLB in the process. These are skills are a rare commodity that haven't been approached by anyone over the past ten seasons. List all the great base runners of the 2000s: Ichiro, Chone Figgins, Derek Jeter, Juan Pierre- none of them have contributed on the level Bourn has through 136 games.
His baserunning skills are only a portion of Michael Bourn's game. We've all witnessed his superb 2009 campaign, and if I do my job, hopefully you all will agree that he has been the Astros' team MVP this season.