Southend United defender Luke Prosser has left hospital after being knocked unconscious in Saturday's 0-0 draw with Cambridge in League Two.
The 26-year-old was taken off on a stretcher after being hit by Ryan Donaldson's second-half free-kick.
He was released from hospital later that day, but is not likely to play in the Shrimpers' next game against Bury.
"Luke is stable, he's fine and he's suffered from concussion," manager Phil Brown told the club website.
"He was released from hospital on Saturday night and we're now going down the PFA guidelines. At this moment in time, he won't be playing against Bury on Saturday.
"He will be assessed and tested on a day-to-day basis."
Former Port Vale defender Prosser has made 32 appearances for promotion-chasing Southend this season.