PITTSBURGH -- Blue Jays second baseman Aaron Hill is back to square one. After visiting a concussion specialist in Pittsburgh on Friday, it was determined that Hill was still suffering symptoms, ruling out a return for the foreseeable future.

The Blue Jays indicated that Hill is out indefinitely, and has been instructed to refrain from all baseball activities for at least two weeks. Hill has been sidelined since being struck on the side of the head by shortstop David Eckstein during a play in Oakland on May 29.

Hill flew ahead of the team to Pittsburgh, where he was examined at the University of Pittsburgh Medical Center's renowned Sports Medicine Concussion Program -- headed by Dr. Michael Collins. After another two weeks, Hill will be re-evaluated.

Since the collision with Eckstein, Hill has battled dizziness, headaches and sleepless nights. Hill needs to be symptom-free for at least a week before the Jays can consider sending him out on a Minor League rehab assignment, which is now out of the question until early July.

In 55 games with the Jays this season, Hill has hit .263 with two home runs, 14 doubles and 20 RBIs. Last season, Hill tied the franchise record for homers in a season by a second baseman with 17, and set a club mark for doubles in a season by a second baseman with 47.

In April, the 26-year-old Hill signed a four-year contract extension worth $12 million with the Blue Jays. The deal also includes club options that could potentially keep the sure-handed second baseman in a Toronto uniform through 2014.