Cumberland missed all of last season after a series of tests showed that he had bilateral vestibulopathy, a condition in which the portions of both inner ears that control balance are damaged.
The condition, coupled with Cumberland's history of concussions, led to incapacitating migraine headaches, sensitivity to light and vision and balance problems. Playing the game, at times, was nearly unbearable for him.
Now Cumberland has some answers and, better yet, is able to resume his playing career.
In early November, Cumberland was referred to the Sports Concussion Institute in Los Angeles, where he underwent an exhaustive round of testing. Cumberland was offered the opportunity to receive his results over the phone Monday, but he opted to fly back, wanting to hear the results first-hand.
"At first, I was sweating bullets because they didn't come out and say that I'd be able to play or not," Cumberland said. "Finally, I'd been I there about an hour talking and they asked me if I had any questions. I asked if I would be able to play.
"That's when they told me that they didn't see why I couldn't."
And with that, a burden was lifted.
Cumberland spent the first five or so months of 2011 traversing the United States, seeing various specialists, undergoing tests at every turn to see what was wrong with him. Then, in June, he was diagnosed with bilateral vestibulopathy at San Diego's Senta Clinic.
It was those same doctors from the Senta Clinic who referred Cumberland to the Sports Concussion Institute in Los Angeles last month.
"They told me that taking this year  off was the best thing I could have done ... to give myself a break," Cumberland said. "It was the first time that I've taken a break like that.
"Right now I feel great."
In order to ward the symptoms that bothered him in the past, Cumberland will now have a daily routine that includes eye exercises, taking up to 900 milligrams of Omega-3 fatty acid [to help keep fluid off the brain] and taking brain games online to help improve brain health and its performance.
"There are three things that I will have to do from now on to help me," Cumberland said. "They will become part of my everyday routine."
Cumberland, who was the 46th overall selection in the 2007 First-Year Player Draft, said Thursday that he hasn't felt this good in a long time.
"I've been working out the last month, preparing myself for anything," Cumberland said. "I've been going up to my old high school with some friends. Since I hate running lines, I've been running pass routes for my conditioning. Then we go to the weight room and lift."
To be sure, it's far better than watching the game, as Cumberland did during the second half of last season, serving as a coach for Class A Fort Wayne of the Midwest League, helping players who were mostly his age.
That was tough for Cumberland, who after his first four seasons in the Padres system has a career .315 batting average, .379 on-base percentage/.429 slugging percentage and 62 stolen bases.
"Drew is a great kid and that was an awfully tough pill to swallow last year," said Randy Smith, the Padres vice president of player development international scouting. "Hopefully he'll be able to resume his career. He's a guy you're rooting for."
Cumberland is eligible for Thursday's Rule 5 Draft at the Winter Meetings but the Padres are hopeful they can retain him, even as both sides know that 2012 could essentially be a transition year for him as he hasn't appeared in a game since July 15, 2010.
There are no guarantees that he returns to his old form. But at this point, that makes little difference to Cumberland, who will turn 23 on Jan. 13.
"I'm excited that I'm getting this opportunity, but at the same time I realize that nothing is going to come easy for me after missing a year," Cumberland said. "I guess that I am trying to keep everything on an even keel.
"But my expectations are the same as they were before -- to reach the big leagues. I hope that I will come out and it will be like I haven't missed a beat. But I know it could take time. That's fine. I'm just thankful to get this chance."