A look at the daily box score lines gives a big hint. Albert Pujols is no longer drawing walks. In his best years, Pujols walked 100 or more times, or about one walk in every seven plate appearances.  This year, Pujols has only seven walks in just over 150 plate appearances.  He's drawn just two walks in the last 21 games.

It’s a good bet that Albert’s low walk total is not because pitchers are suddenly throwing him a lot of strikes in 2012. When Pujols had little skids with the Cardinals over the years, it was usually because he was chasing pitches outside the strike zone and/or trying to pull outside pitches.  The few Pujols at bats that I’ve seen either in highlight packages or during televised games leads me to believe that he’s chasing a lot of pitches that are outside the strike zone.
When I have seen him swing at strikes this year, he still drills the baseball.

The first rule of hitting is to get a good ball to hit.  This applies to baseball, slow pitch softball and even golf. In golf, you set up to hit where the club will strike the ball (hopefully for us duffers and hackers...) in the most effective way possible. You should be able to hit the ball well on every stroke in golf.  In baseball and softball, you get the best results by swinging at a pitch that you can hit well. With few exceptions, that is going to mean a ball in the strike zone.  Looks to me like Pujols has drifted away from this fundamental.

I think that the Angels batting order is a second factor.

In St. Louis, Pujols had the likes of Jim Edmonds and Scott Rolen in the prime of their careers adjacent to him in the batting order.  At various times in his career, Pujols has also had the likes of  Lance Berkman,  Larry Walker and Mark McGwire in Cardinal batting orders too.  Those hitters scared people.

With the current Angels, it’s  Torii Hunter, Kendry Morales,  Mark Trumbo and Mike Trout are the guys around Pujols in the batting order.   Hunter and Morales are solid ballplayers,  but not on the level of what the supporting cast was and is in St. Louis.

Looks to me like Pujols needs to do two things…
1—Demand strikes. Get a good ball to hit.
2—Take the walks. Trust the rest of the batting order.