"We're trying to get a better understanding of what is there -- if that's a way to describe it," said manager John Farrell. "We're sending him to see Dr. Collins at the University of Pittsburgh. Just the fact that he's still shown, or is still experiencing the same types of symptoms -- we just want to get our arms around it as best we can."
Drew is expected to return to Spring Training on Thursday. At this stage, it's doubtful he will open the season on the active roster.
"I mean, that window is closing by the day," Farrell said. "When you talk about an ordinary or somewhat normal number of at-bats in Spring Training, yeah, those opportunities are starting to be removed."
At this point, however, the Red Sox are far more concerned about Drew's well-being than when he might play again.
"Well, his care is first and foremost," Farrell said. "And I guess the fact is, we're still in Spring Training. We know the days are ticking by, but whether it's precautionary or whatever measure we can take with his care being first and foremost, we're going to do that. That's the best I can tell you right now."
Orioles second baseman Brian Roberts knows full well what type of things Drew will be tested for in Pittsburgh, having gone through it himself. Roberts has had two concussions.
"They do a battery of testing," Roberts said before Tuesday's Grapefruit League game against the Red Sox. "They do one which is the ImPACT test on the computer, but then there's a whole bunch of other things that they do there at the facility that most people don't see or don't know.
"There are a bunch of other things to find out in the testing, like what area of the brain has been affected and what needs to be looked at. What needs to be rehabbed. There's a little bit of everything. They'll do some ocular testing, some vision testing. So there's numerous areas of the brain that can be affected."
The one thing Drew has going for him, according to Roberts, is that the person he is going to see is one of the best.
"I'd say he's going to see a great guy," Roberts said. "I think that it's a scary situation, and I would tell him to trust his instincts, to trust what he's feeling and know that there is an end in sight. But in the midst of it, it's a really tough place to be. I think the hardest part of that injury is that people don't have any idea what's going on because they can't see it."
Roberts can empathize with everything Drew is going through.
"I hurt for him. I feel for him, because I know what it's like," Roberts said. "But I think the thing you've got to realize is, you've got to be careful. It's the rest of your life; it's your brain. Make sure that you're right before you do anything. I think the biggest thing is, he sees so many cases, he's done a lot of research. He knows that everyone is different, but they also have a way of understanding what part of the brain has been affected and how to help rehab that."