"It's a shame because he had been really swinging the bat well," Amaro said. "He was disappointed. We're disappointed. Hopefully it won't be a long-term thing. He already felt better [Saturday]. We'll see."
Joseph, the Phillies' No. 16 prospect, was the centerpiece in the trade with San Francisco for Hunter Pence in 2012 and was considered one of the top catching prospects in the game at the time. He was limited to 36 games last season because of persistent concussions symptoms.
"He was doing fine. He had a very good winter ball and went through spring fine," Amaro said. "He took a tough foul tip, I guess, and it jarred him. The concussion stuff is scary. So we'll monitor him and see how it goes."
Jesse Sanchez is a national reporter for MLB.com. Follow him on Twitter @JesseSanchezMLB. This story was not subject to the approval of Major League Baseball or its clubs.