Shields told the paper that he was dealing with "excruciating pain" and that he "wasn't feeling good."
The right-hander is scheduled to start Game 1 of the World Series against the San Francisco Giants on Tuesday.
“I probably could have used the extra day (of rest),” Shields said. “But I just told them ‘Whenever you need me, I’m ready to go.’”
Shields has yielded fewer than four earned runs only once over his three starts this postseason and has pitched a total of 16 innings.
- Chris Johnson