Batting average is a bad way to measure players, and a really bad way to measure Ortiz.
I can't emphasize enough how small of a deal this is. Last year Ortiz had a great year, he OPS'd .953 and hit 29 home runs in a full season. In April 2011, he went .267/.373/.395. In July of that year, he hit .253/.361/.458. In May 2012, he went .250/.341/.500.
It's all in the peaks and valleys of the season. I urge you not to worry.