Wigan Athletic boss Paul Jewell says goalkeeper Chris Kirkland suffered shock as a result of a blow to the head at Middlesbrough.
The former Liverpool custodian suffered the injury shortly before half-time of Wigan's 1-1 draw with Boro at The Riverside on Saturday.
Kirkland took a knock to the head when he claimed a Stewart Downing free kick and needed extensive treatment as a result.
He finished the half in goal, but did not return for the second half, with substitute Mike Pollitt coming on in his place for the restart.
Jewell then revealed the severity of the 25-year-old's condition when he was put in a neck brace and given oxygen in Wigan's dressing room before being taken to hospital.
"Chris Kirkland went into shock," Jewell said. "He was surrounded by six or seven paramedics and they were concerned, very concerned.
"He got a kick or a knee in the head. He got up after attention and he came in, but it was a delayed reaction, apparently.
"The oxygen was on him and the neck brace and there was a lot of concern for him.
"I saw him come in and the next thing, he was on a bed. He has gone to hospital, but the good news is we think he is okay.
"In the ambulance, he did apparently say to tell the gaffer he would be okay for Wednesday (at home to Arsenal). He must have had a bang on the head."
The distress of seeing Kirkland in trouble looked to have made it difficult for Jewell and the keeper's team-mates to remain concentrated at half-time, as Boro dominated the second half in claiming a valuable point at The Riverside.
Jewell was happy with Pollitt's performance and praised Boro goalkeeper Mark Schwarzer for a string of excellent first-half saves after Wigan looked the brighter side up to half-time.
"He [Pollitt] is a good keeper - but he did not do as well as their keeper, though," added Jewell.
"He made three unbelievable saves and if we had gone in at half-time 5-2 up, I do not think it would have been too unfair.
"Chris made a couple of good saves himself, but two of the saves Schwarzer made were just unbelievable."