Why scoring is down in the AL, and why it might stay that way - Tim Marchman - SI.com:
"...At the margins, the value that teams such as the Boston Red Sox and Seattle Mariners are placing on defense probably encourages these trends. A slight preference for fielding over hitting removes a few players like Jermaine Dye from lineups and adds a few like Casey Kotchman, leading to fewer balls falling in for singles and fewer balls clearing fences. Tip your cap to the math wizards here...Strikeout rates have risen to the point where they may actually be affecting hitters' ability to get on base...."
Striking out is OK if it accompanies a lot of HRs.