http://www.baseballprospectus.com/statistics/postseasonodds.php 

While browsing through BP I found this interesting simulation, it was on last year's playoff, based on matchups and homefield advantage. anyway... the results were... interesting.

This was the odds on October 1st, after all teams have made it and before the first game was played of each team actually winning the WS.       

 LAA: 13%   TB: 13%  CHW : 5%  BOS: 19%   CHC: 30%  PHI: 5%  LAD: 5%  MIL: 7%     

Some obvious thoughts.

1. Is there a better proof of god messing with the Cubs? they had the BEST odds of  making the WS and winning it (they had over 50% chance of winning the pennant!!) and they don't make it out of the first round, AGAIN.

2. The AL teams' chances dramatically reduced because they're all pretty good and evenly matched. 

3. The Phillies won on just 5% chance.

4. Everyone had at least 5% chance and no one had more than 30%

This seem to be a rather solid confirmation of the playoff is a crapshoot theory. as even the best odds team only had a 30% shot , and even the worest one have a 5%, this is drastically different than the NBA where the 8th place team NEVER wins.  while the top place finisher are highly likely to advance.

So within the confine of these odds. what is the effect of one player really? we need someone that have a better insight on exactly the methodology used in this calculation, but I'd hazard a guess that even a Bondsian player isn't going to shift the odds THAT dramatically.