"I felt it tug and bite a little bit," Millwood said. "It didn't pop, so that's good. The doctor doesn't think it's real bad."
Millwood tried to remain in the game, but gave up when he couldn't push off the rubber without pain.
"Hopefully, it's not too bad," he said. "I'm really not as concerned as I am frustrated. It's been a frustrating year so far."
Millwood will have an MRI on Thursday. Manager Eric Wedge deemed Millwood's injury as "considerable" and said there's a possibility the right-hander may go on the 15-day disabled list.
Maybe Wedge is just being pessimistic. Millwood has quietly had a nice start to his season:
59 IP, 3.20 ERA, 1.27 WHIP, 46/15 K/BB.
Hopefully, he comes back quickly.