Atletico Madrid say striker Fernando Torres is "conscious and stable" in hospital after suffering a head injury in the 1-1 draw with Deportivo.
The ex-Liverpool and Chelsea striker fell heavily after an 85th-minute aerial challenge by Alex Bergantinos.
The Spain international, 32, appeared to be unconscious while being tended by his team-mates, then Atletico medics.
He will spend the night in hospital under observation but scans show he has "no traumatic alterations or injuries".
Speaking at his post-match news conference, Atletico coach Diego Simeone said he was "worried and nervous" when the incident happened.
"We heard the blow from the bench, we saw how he fell and we were afraid," he said. "We didn't know if that noise was Fernando's neck or not."
Atletico finished the game with 10 men, having used all three substitutes, but earned a point thanks to Antoine Griezmann's stunning 30-yard strike.
Deportivo had taken an early lead in Pepe Mel's first game in charge when Florin Andone capitalised on a poor Jan Oblak goal kick.
The draw leaves Atletico fourth in La Liga - 11 adrift of leaders Barcelona - while Deportivo are now 17th.