Yes, Ryan Howard will be out a while. According to Matt Gelb of the Philadelphia Inquirer, Ryan Howard has been placed on the 15-day disabled list with a knee injury. Howard was scratched just about an hour ago, after previously been scheduled to bat fourth and play first base in tonight's contest against the Altanta Braves.
Darin Ruf, buried in the minors after a so-so Spring Training in left field, will replace Howard on the roster. Ruf was hitting .266 with seven home runs and 46 RBI at AAA Lehigh Valley. Ruf headed to AAA planning to play occasional first base with the idea that he could cover first base in case of a Ryan Howard injury. They will need him to do just that.
Gelb says that Ruf was in Lehigh Valley and is expected to arrive at some point during tonight's game against the Atlanta Braves.