MILWAUKEE -- The Blue Jays are still trying to establish some sort of timetable for Aaron Hill's return from the concussion he suffered nearly three weeks ago. It's been a difficult task, considering the second baseman continues to struggle with symptoms.

The next step in Hill's recovery process is scheduled for Thursday, when he'll travel to Pittsburgh one day ahead of his teammates in order to visit a concussion specialist with the University of Pittsburgh Medical Center's renowned Sports Medicine Concussion Program.

"He's going to get checked out in Pittsburgh," Blue Jays manager John Gibbons said. "I don't know if he's exactly symptom free, but he's feeling much better."

Dr. Michael Collins -- a neuropsychologist at the UP Medical Center -- heads the clinic in Pittsburgh, where Toronto opens a three-game Interleague series with the Pirates on Friday. Gibbons said Hill has felt better during the past few days, but he still needs to be cleared to play a Minor League rehab assignment.

If Hill is deemed symptom free -- something he said wasn't the case as recently as Saturday -- the Jays will wait a week before sending their second baseman on a Minor League rehab assignment. That being the case, it could still be 10 days or longer before Hill is activated from the disabled list.

"If he's symptom free between now and then," said Gibbons, referring to the trip to Pittsburgh, "and that guy gives him the OK, then he's ready to resume activities. He wouldn't go right back into games. We'd push him and condition him a little harder.

"He's got to play some games [before being activated]. He's going to have to get in shape before he plays those games, too. The longer he's out, he's falling out of baseball shape."

Hill, 26, was struck on the side of the head during a collision with Toronto shortstop David Eckstein during a play against the A's on May 29 in Oakland. After the game, the injury was described as a "mild concussion," but Gibbons didn't believe Hill would miss much time.

"I didn't think it was that serious," Gibbons said. "But, saying that, heads are heads."

Since then, Hill has battled dizziness, headaches and sleepless nights. Hill said on Saturday that he was later told that he may have suffered a Grade 2 concussion, which typically requires at least a week off before a player can consider returning.

Hill noted that his neurologists have discussed his situation with Corey Koskie, who suffered a concussion in July 2006 with the Brewers and hasn't played since. Hill said they've also talked to the trainer for Mets outfielder Ryan Church, who is currently on the DL due to post-concussion syndrome.

"With this type of thing, it's more than just for your team," Hill said on Saturday. "It's your career and your life and your family. When I think about that, it quiets me down a little bit. I think I'm giving myself headaches with how mad I've been getting lately. For me, it's unacceptable how long it's been.

"For some people who don't understand, it's like, 'Why cant you just play?' That's what kills me, because I hate this, man. We're in the middle of things and I've got nothing to do."