Since Garrett Jones struggles mightily against left-handed pitchers, the Pirates will employ a platoon at first base. Last season, Jones had uncharacteristic difficulties handling sliders. This should not be a worry for Garrett moving forward. He will, however, continue to be a defensive liability.
Casey McGehee followed up strong 2009 and 2010 seasons with a dud in 2011. This was partially due to bad luck (.249 Batting Average on Balls In Play vs. career .290). Regression to the mean alone will lead to improved stats, with potential for recapturing his previous success.
A resurgent McGehee could push Garrett Jones to a limited pinch-hitting role. His defensive track record at first base is nonexistent, but his performance at third base suggests he will not be an improvement over Jones.