There are a few reasons for that:
First, Wigginton led the team with a .378 on-base percentage entering Tuesday. He was second with a .436 slugging percentage.
Second and third, Polanco was hitting .200 and the Phillies said they are trying to monitor his playing time because of his injury history.
"We're trying to get him going good," Phillies manager Charlie Manuel said of Polanco. "But I try to monitor his time a little bit. Tonight, I like Ty at third because he hits good in this yard. Polly has better numbers on the guy tomorrow [Arizona right-hander Trevor Cahill]. I didn't plan on Polly playing the whole series. That was my thinking."