Considering the manifying glass that these players are under today (with Perry and Lou noticing Lee changing his hip motion at the plate for example) the Cubs would know if Z is hurt. Let's by honest, the guy is a great athlete, but isn't in the best of shape. He's going to get dehydrated on hot days if he isn't careful, and we all know he goes through ups and downs when his head isn't on straight. Hopefully this news will allow him to refocus on mowing down the Cards on Sunday.