COLUMBUS, Ohio -- A missing Ohio State football player told his mother in a text message the day he disappeared that concussions had his head messed up, according to a report filed with police.

Kosta Karageorge, a 22-year-old senior defensive tackle from Columbus, was last seen at his apartment around 2 a.m. Wednesday. Team spokesman Jerry Emig confirmed that Karageorge missed practice Wednesday and Thursday, which his family says was uncharacteristic.

Karageorge's parents filed a missing-person report Wednesday evening, listing him as white, 6-foot-5, 285 pounds, bearded and bald.

His mother, Susan Karageorge, told police he has had several concussions and a few spells of being extremely confused, according to the report. She said that at about 1:30 a.m. Wednesday, he texted a message that cited the concussions and said, "I am sorry if I am an embarrassment."

The team's physician, Dr. Jim Borchers, said Friday that he could not comment on the medical care of student-athletes. But, he said, "We are confident in our medical procedures and policies to return athletes to participation following injury or illness."

The player's sister, Sophia Karageorge, told The Columbus Dispatch that he apparently was upset, and roommates said he went for a walk, dressed in black from his hat to his boots.

"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 that after each concussion, he followed trainers' instructions and received proper care but "his repercussions from (concussions) have been long-term or delayed."

She said he was without his wallet and his motorcycle.

Columbus police are investigating Kosta Karageorge's disappearance as a missing-person case, the Dispatch reported.

"Certainly a young adult male is allowed to go off the grid for any period of time," police spokesman Sgt. David Pelphrey told the newspaper. "At this point, the family has expressed some concerns, and in response to their concerns we're ramping up our efforts."

Ohio State coach Urban Meyer was emotional as he addressed the situation after the Buckeyes' victory against Michigan on Saturday.

"Our prayers and thoughts are with him and his family and to have him return home safe," Meyer said. "It's one of those, all you can do is grab a knee and pray hard. Not one person can make it through this kind of week. You need your strength. I know there were a lot of prayers on the team because there are a lot of guys who are friends of Kosta."

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

Ohio State University's football stadium went silent as an announcer called out Karageorge's name and a police poster seeking information on his disappearance appeared on a scoreboard.

The announcer said the entire university community was concerned about Karageorge and hoping for his safe return. Polite applause from among the 105,000 fans broke the silence at the end of the recognition.

"He was only with his us since August, so I didn't know him that well," Meyer said. "But I talked to his mom a few times. (The message for him) was just, 'Come home safe, man.'"

During halftime at the No. 16 Ohio State men's basketball game against James Madison in Columbus, pictures of Karageorge were shown and an announcement was made urging people with any information to contact police.

About 100 people gathered Friday afternoon in Columbus to spread fliers with his photo and description.

The Associated Press contributed to this report.