Mackanin said he didn't know when Altherr sustained the injury, but that he came in after the seventh and "said he didn't like the way it felt."
Hyun Soo Kim, Daniel Nava and Odubel Herrera are options to play right field if Altherr is sidelined, Mackanin said.
Altherr missed 10 games in July with a hamstring strain, returning July 26. He had played seven of eight since coming back, sitting out Wednesday against the Angels.
On the season, Altherr is slashing .285/.357/.536 with 16 home runs and 47 runs scored. Since his July 26 return, he's hitting .258/.343/.516 with two homers.
Max Gelman is a reporter for MLB.com and covered the Phillies on Friday. This story was not subject to the approval of Major League Baseball or its clubs.