Chalk it up to the steroid testing policy which wasn't beefed up--pardon the pun--until 2005 with worthwhile penalties (A first positive test resulted in a suspension of 10 games, a second positive test resulted in a suspension of 30 games, the third positive test resulted in a suspension of 60 games, the fourth positive test resulted in a suspension of one full year. Later that year, the penalties were changed to: first positive test, 50-game suspension; second positive test , game suspension, third positive test would result in a lifetime suspension from MLB), offense in baseball in 2008 has been noticably lower than in recent years.
Projecting runs scored for this year (22,192 runs) through the end of the season would yield the lowest total since 1997.
Projecting homerun output this year through game 162 would give a total of 4788 homeruns. The lowest total since 1997.
The most glaring stat is the historical ERA numbers since 1996.
While ERA has come down since it's peak in 2000, its continued to oscillate up and down somewhat since. However, the first sharp drop in ERA occurred in 2001, four seasons before the first real strict steroid penalties took effect and 2 years before testing began. Is this a result of steroid testing or just a function of the randomness of baseball?
So far, 2008 ERA numbers are on pace for the lowest level since the second expansion era began in 1993, that's 16 seasons.
While homerun numbers are down 8% from 2006 to 2007 and a projected 3% from 2007 to 2008, Doubles are up 4% since 2003. What does this mean? Either steroid testing is working in that performance enhancing drugs aren't as prevalent as they were 10 years ago and/or the lack of pitching talent has weeded itself out of the big leagues since its dillusion due to expansion in the early and mid 1990s. Give it another couple of seasons to see if a trend develops from homerun hitting to doubles hitting and much lower ERAs.