Silva won't pick up a baseball for upwards of a week, which could mean a possible stint on the disabled list. Manager Bud Black said that a determination could come on Friday.
"We're giving it another day to see if it quiets down," Black said.
Silva said that he sustained the injury during his first at-bat in the second inning, an at-bat that resulted in a single, his first Major League hit.
"I felt it getting tight when I went back to the mound, but I thought that it was cold weather. I didn't pay much attention to it," said Silva, who allowed five runs over five innings and did not earn a decision in a game that the Padres eventually won, 6-5.
Even after leaving in the fifth inning on Monday after allowing a three-run homer to David Wright, Silva didn't think much of the injury. But it wasn't until he woke up on Wednesday that he knew there was something wrong.
"The next day, there was a bruise," he said. "I've never had this before."
The Padres haven't announced who will take Silva's place in the rotation on Sunday, but it could be Josh Geer, who is scheduled to start that day for Triple-A Portland. Geer is 1-1 with a 3.60 ERA in two starts for the Beavers.
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.