For a while CC was (almost?) exclusively starting him against LHP, whom he has done poorly against. I see no support against the notion that he should have played more against RHP than LHP (other than hoping he could reverse his reverse-splits). If you take away 10 AB vs. LHP and give him 40 AB vs. RHP, his overall numbers would go up appreciably.
Keston's OPS vs RHP is 1.069, and more than .250 more than the next best batter Caratini (.806).