There's no question about it, the shift is a pointless maneuver. If it was effective, you would see a noticable decrease in BABIP (Batting Average on Balls in Play).
From 2010 - 2013, Ortiz has posted a .314 BABIP. From 2003 - 2006, Ortiz posted a .298 BABIP.
League average BABIP from 1990 - 1995: .292
League average BABIP from 2007 - 2012: .299
If anything, playing defenders out of position could well be one of the (likely many) factors in the increase in BABIP.