Walks are an important source of the baserunners needed to create more runs. There is a direct correlation between on base percentage and runs scored, but too often we focus just on the batting average part of OBP, and spend little time on walks.
But patience at the plate is more than just the ability to draw a walk. It is also about fouling off tough pitches and making the pitcher throw until you get one you can drive. It is also about making the other teamsí pitchers burn through their allowed pitch count, and getting into the bullpen earlier. Most teams are weakest in their middle relief corps, those 5th, 6th, and sometimes 7th inning guys.
Those of us that watch most of the games have a subjective sense as to who is giving us quality at bats, those 8 or 9 pitch ABs that really test the pitcherís mettle. But what stat best corresponds to quality at bats? I would submit that pitches seen per plate appearance(P/PA) is one of the best measures of this, and you will see how it often correlates with walk rates.
Walk rate here is in the same form as used for batting average. So if one player is .100 higher than another, that will effectively mean that their OBP is 100 points higher.
Below are the 2009 stats to date, in rough order of where each player hits in the lineup. I have also included the 2008 P/PA stat so you can see if the player is becoming more or less patient.