Just doing a little research, probably worthless, but I'll post it here:
2010 Playoffs - 8 out of 29 games decided by less than 2 runs (28%)
2009 Playoffs - 10 out of 30 games decided by less than 2 runs (33%)
2008 Playoffs - 8 out of 32 games decided by less than 2 runs (25%)
2007 Playoffs - 4 out of 28 games decided by less than 2 runs (14%)
2006 Playoffs - 4 out of 30 games decided by less than 2 runs (13%)
So, don't assume it's the playoffs and every game will end up a close one.
2010 Playoffs - 8 out of 29 games decided by less than 2 runs (28%)
2009 Playoffs - 10 out of 30 games decided by less than 2 runs (33%)
2008 Playoffs - 8 out of 32 games decided by less than 2 runs (25%)
2007 Playoffs - 4 out of 28 games decided by less than 2 runs (14%)
2006 Playoffs - 4 out of 30 games decided by less than 2 runs (13%)
So, don't assume it's the playoffs and every game will end up a close one.