Motherwell midfielder Carl McHugh suffered no damage after being knocked unconscious during Sunday's defeat by Celtic, initial tests showed.
The Irishman was carried off on a stretcher after being knocked out cold in an aerial challenge with Odsonne Edouard.
An update on Motherwell's Twitter account read: "Carl McHugh was released from hospital on Sunday night.
"A CT scan showed no damage to his head or neck. He will now go through the concussion protocol, automatically ruling him out of Wednesday's game with Kilmarnock."
McHugh, missed almost five months of the 2016/17 season with concussion and was also taken to hospital after a clash of heads with team-mate Charles Dunne during a Boxing Day defeat by Kilmarnock last year. He missed one game before returning after the winter break.