According to the club, such irritation is not uncommon in Tommy John surgeries and the ligament, repaired by Dr. James Andrews, is not involved.
Crawford said he wasn't sure what caused the flare-up, only that he "ramped up the activity" when he started to face live pitching in batting practice. He's been prescribed a week of rest and anti-inflammatory medication.
"There doesn't seem to be any panic," said Mattingly. "We're still being cautious. I look at this as more of a setback than I did the last couple of days. He can't throw and hit. He can still track [pitches], do baserunning, fly balls. He can still do work. But this pushes it back a bit."
Crawford said the diagnosis was a "relief" because he was worried it was something worse.
"I suddenly got this feeling, it just felt weird," said Crawford. "They said it was OK, no ligament, a little stinger nerve. There was tightness and soreness from overworking. I had a date in mind that I tried to reach and overworked. They say it's normal, nothing to worry about. Put me at ease."
The Dodgers acquired Crawford -- and more than $100 million in salary obligation -- in last summer's blockbuster trade with the Boston, two days after he underwent the operation on his left elbow. It was hoped that Crawford would be ready for Opening Day, but Mattingly conceded that now is in doubt.
"This definitely challenges the timing of it," Mattingly said of Opening Day. "Instead of having four weeks, we'll have three. There's still time. But I'd rather he came back after 10 days or 20 days and have him healthy for a solid 140 [games] than have him in and out."
Crawford said he had been targeting to get in a game Thursday. He's still targeting to be ready for Opening Day.
"I understand there's a chance I might not be ready the first [of April]," he said. "At the same time, that's still a goal of mine.
"It's frustrating, but it's for my own good. I have to be patient and wait it out. My time will come. I just want to be out there."
Extra outfielders Skip Schumaker and Jerry Hairston would figure to share the starting duties if Crawford opens the season on the disabled list. The Dodgers seem to be leaning toward also keeping Alex Castellanos, in part because he gives them a needed right-handed bat and a defender that can play all three outfield positions. Another possibility is Tony Gwynn, although as a non-roster player he would require a roster move.