Ellsbury will see Dr. Lewis Youcum at the Kerlan-Jobe orthopaedic clinic on Wednesday morning.
"He came in and worked out today, [and] I think he has a 5 o'clock flight out to the West Coast," said Red Sox manager Terry Francona. "He'll be examined thoroughly. Whatever that entails, they have our blessing. We need to try to get as much information as we can."
Ellsbury suffered a hairline fracture of four left ribs on April 11, when he collided with teammate Adrian Beltre in pursuit of a foul ball. The outfielder was activated on May 22 and played in three games before recurring discomfort forced him back to the disabled list.
Francona has been in contact with Scott Boras, who represents Ellsbury, the past couple of days.
Ellsbury will meet up with the Red Sox again when the club gets back to Boston on Friday. He is eligible to be activated on Saturday, but it would be a big surprise if Ellsbury returned that soon.
More than anything, the Red Sox hope that the visit with Yocum, who is one of the most renowned sports orthopedists in the world, will put Ellsbury's mind at ease.
"I hope there isn't something new. I think they're just trying to get to the bottom [of it], or if nothing else, get an opinion that's completely removed from everyone that's around him," Francona said. "Hopefully we'll get some news, and they'll say, 'We know you feel this, we understand that, and you can build up and you're not going to hurt yourself.' But we don't know. That's why we're sending him. We just want to get as much information as we can."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.