COLUMBUS, Ohio >> An Ohio State football player reported missing after he uncharacteristically skipped two practices has a history of sports-related concussions, and his family worries he might have become disoriented, his sister said.

Kosta Karageorge, a senior defensive tackle from Columbus, was last seen at his apartment around 2 a.m. Wednesday, his sister, Sophia Karageorge told The Columbus Dispatch. She said her 22-year-old brother apparently was upset, and roommates said he went for a walk, dressed in black from his hat to his boots.

Police said a missing-persons report was filed on the bearded, 6-foot-5, 285-pound former wrestler.

Team spokesman Jerry Emig confirmed that Karageorge missed practice Wednesday and Thursday.

Ohio State coach Urban Meyer described Karageorge as a hard worker and an important player in practice.

“Our thoughts continue to be with the family of Kosta Karageorge, and we pray that he is safe and that he is found soon,” Meyer said in a Friday statement.

Karageorge, a former Buckeyes wrestler, joined the football team as a walk-on this season. He has played in one game and is among two dozen seniors slated to be recognized at their final home game Saturday against rival Michigan.

Karageorge’s sister said he left without his wallet or his motorcycle. He has a history of concussions, including one a month ago, and might have become disoriented, she said.

“We’re very concerned that he’s not himself and that he maybe doesn’t know what’s going on,” she told the newspaper. She said after each concussion, he has followed trainers’ instructions and received proper care, but “his repercussions from (concussions) have been long-term or delayed.”

The team’s physician, Dr. Jim Borchers, said Friday that he could not comment on the medical care of student athletes.

But, Boarches said, “We are confident in our medical procedures and policies to return athletes to participation following injury or illness.”

The Dispatch reports that about 100 people gathered Friday afternoon in Columbus to post fliers with the player’s photo and description.