Bobby Abreu invigorated the 2009 Angels with his high OBP. His .390 mark that season not only helped the Angels offense, but inspired other hitters on the team to be more selective at the plate. Bobby was a perennial .400 OBP hitter during the peak of his career, but that stat started falling in 2007, and 2009 may have been his last hurrah as he dropped to .353 in 2010, the lowest level he ever posted in a full season.
The following graph shows Bobby's ball and strike rates over 2009 and 2010 (click graph for a larger version):
Note that in 2009, Bobby played two stretches in which his ball rate (the green line) was much higher than his strike rate (the blue line). In 2010 that reversed, with two periods of much higher strike rates than ball rates. Since walks are a part of Bobby's OBP, fewer balls meant fewer walks, and he drew seven fewer in 2010 than in 2009.
The drop in ball rate was attributable to two changes. Bobby was putting more balls in play outside the strike zone, and getting fewer balls called in the strike zone:
|Number of Pitches||2009||2010|
|Called balls in zone||124||106|
|Strikes outside zone||364||364|
|In play outside zone||80||98|
The umpires were less forgiving, but it also seems that Bobby was fishing outside the zone more. It's tough to say if one caused the other. From the above graph, it was clear Abreu was not getting ball calls early, which may have caused him to to start swinging at pitches he would normally take. The change led to 19 fewer hits, and a lower OBP.
Bobby is off to a good start in 2011 with seven hits and four walks in his first three games. Maybe the calls are going his way again.