"The prognosis doesn't sound too good," Amaro said. "I think it's something that's going to take a while. … Whoever we think is an upgrade, whether it's defensive or offensive. We'd like to probably get a little bit better. John [Mayberry Jr.] is a good center fielder. He's not a plus defender. So if we can get a better one than that, that'd be good."
Losing Revere to injury is a blow to the Phillies, whose offense has picked up in recent weeks. Revere was hitting .347 since the end of April, which is the sixth-best mark in baseball in that span. His .380 on-base percentage was 19th out of 164 qualifying hitters.
The Phillies activated catcher Erik Kratz to take Revere's spot on the roster, although it seems likely the team will not carry three catchers following the All-Star break.
"It's one of those deals," Revere said. "It's part of the game. I've probably hit a couple balls on the same spot a couple times and really nothing happened, except a bruise. But it was good the next day. But this was finally the one that cracked it."
The Phillies also are looking internally at options in center. They recently started playing Triple-A Lehigh Valley second baseman Cesar Hernandez in center, but they have accelerated his learning curve. He had been scheduled to play in the International League's All-Star Game this week, but the Phillies are sending him to Double-A Reading to play center instead.
"He'll be playing exclusively in center field to see if that's an option for us," Amaro said. "He struggled yesterday, , but it's a new position for him. But we'll give him a shot."
Triple-A shortstop Freddy Galvis has played some outfield for the Phillies, but Amaro indicated center field is not an option for him.
So make that two spots the Phillies say they are trying to upgrade before the July 31 Trade Deadline: bullpen and center field.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.