Ethier was back in the clubhouse at AT&T Park after Wednesday night's game, but wouldn't elaborate much beyond the club's prepared statement.
"I'm not worried about that," he said when asked about the postseason. "I'm worried about tomorrow. Does the postseason start tomorrow? All right then. We're just worrying about tomorrow."
Ethier originally injured his left ankle on a swing in Colorado on Sept. 4 and reinjured it on a double against the Giants on Sept. 13, the last time he played. After more than a week of therapy, he encountered increased pain trying to round the bases in a workout Tuesday, leading to Wednesday's exam.
"Yeah, I'm a little worried about him," said Mattingly. "He didn't look good and wasn't running very hard. I'd like to be optimistic. It was the same thing with Matt [Kemp] about turning [the bases] and two days later he was rolling. That would be great. We'll just see. Today we sent him to rule out anything in a different direction."
The club is calling the injury a left ankle sprain. Ethier said the discomfort he has is believed to stem from the periosteum, the sheath that covers the bones of the leg, with pain similar to shin splints.
Although he insisted the club hasn't internally set rosters, Mattingly indicated he would not be comfortable carrying Ethier for strictly pinch-hitting purposes.
"He's got to be able to run the bases," Mattingly said. "Yesterday he was a little disappointed. He had the off-day and said he was perfectly fine. Shagging in the outfield he looked really good, a little cautious, but then the turns disappointed him. The fear is it's taking longer. He's been out 11 days. We're running out of time again."
If Ethier is not on the roster, it might open a spot for Scott Van Slyke, who has played primarily outfield, or Jerry Hairston, who might otherwise be squeezed off the roster by newcomer Michael Young. As right-handed hitters, Van Slyke or Hairston would give Mattingly a platoonmate for left fielder Carl Crawford against left-handed pitching.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.