Mark J. Rebilas/US PresswireAndre Ethier's slugging percentage has fallen from .493 in 2010 to .428 this season.Andre Ethier's OPS has dropped below .800 for the first time since April 3. He has 10 home runs this season and one in his past 107 at-bats.  All this is feeding some simmering frustration about his 2011 performance and even making me wonder to myself ever so briefly whether he might be on a downward, James Loney-like trajectory.And then, you take a step back and see that in 2011, Ethier has ...a .294 batting average that is .002 higher than last year's and .003 higher than his career average.a .367 on-base percentage that is .003 higher than both his 2010 and career averages.5.71 doubles per 100 plate appearances, compared with 5.64 in 2010 and 5.84 in his career.Mo