Jared Gaither took part in practice on Wednesday after missing nearly two months with a thoracic disc injury in his back.
Thursday, his lower back flared up again, and now, the Ravens will have to send their offensive tackle to a specialist to find out exactly what's going on.
"He said he was feeling better and he'd be able to go next week, he thought, so he went out there and went through a very light practice," head coach John Harbaugh said. "The next day, [he] came in and his back was sore. So, we're sending him for a re-evaluation."
Gaither will fly out to California on Monday and meet with Dr. Watkins, who is the same back specialist that Gaither saw when seeking a second opinion on his injury back in training camp.
"Our doctors have looked at it, and they don't see it in there right now," Harbaugh said. "So we've got to find out from the best experts what's causing that problem."
At some point, if Gaither continues to be unable to get back on the field, the Ravens will have to make a decision on whether to put him on Injured Reserve.
"Obviously, the clock is ticking on something like that," Harbaugh said.