Fernando Torres was hospitalised after being involved in a collision late in Atletico Madrid's 1-1 draw at Deportivo La Coruna on Thursday.
Initial tests showed no signs of any serious spine or head injuries after Torres collided with Depor's Alex Bergantinos while jumping for the ball in the 84th minute, and the club released a statement on Friday morning saying he would undergo further tests but had spent "a good night" in hospital.
- Atlético de Madrid (@atletienglish) March 3, 2017
Torres' head slammed into the ground upon landing before players and medical staff rushed to his aide. After being attended to for five minutes, he left the pitch on a stretcher that carried him to a waiting ambulance, which transported him to a local hospital.
Atletico released a statement soon after the game ended that said: "Fernando Torres has suffered a traumatic head injury and has been transferred to hospital for tests.
"Our player, who is stable, suffered a heavy blow to the head in the final stretch of the match and had to be removed by ambulance quickly to a hospital. The Rojiblanco striker will spend the night under observation."
The club later updated Torres' statement by saying a CT scan showed "no alterations nor traumatic injuries," and the player himself was soon able to tweet his thanks for support.
"Thank you very much for worrying about me and for your messages of support," he wrote. "It was just a scare. I hope to be back very soon!"
Muchas gracias a todos por preocuparos por mí y por vuestros mensajes de ánimo. Ha sido sólo un susto. Espero volver muy pronto!
- Fernando Torres (@Torres) March 2, 2017
Atletico coach Diego Simeone said he could hear the sound of Torres' collision from the bench.
"We still don't have any official information but he's conscious," he said in his postgame news conference. Worried, nervous... those are the feelings after he suffered such a heavy blow.
"We heard the blow from the bench, we saw how he fell and we were afraid. We didn't know if that noise was Fernando's neck or not. They are unfortunate situations that happen in matches and we're hoping for the best for Fernando."
Filipe Luis said after the game that the initial news was more positive than the injury first appeared.
"It was something very scary for all of us, we are not used to such sights," Luis said on BeIN Sports. "The news we have received so far is positive, he is conscious and speaking.
"The most important thing is Fernando is OK and recovers. He means a lot to this club, both as player and person. These things happen in football. We hope that he is OK, and back with us playing soon."
Torres had entered the game as a substitute for Kevin Gameiro 20 minutes earlier.
Depor had gone 1-0 up on 13 minutes when Florin Andone capitalised on a mix-up between Atletico goalkeeper Jan Oblak and defender Jose Maria Gimenez, with the home side dominating in new coach Pepe Mel's first 45 minutes in charge.
Atletico hit back after the break when Antoine Griezmann caught out Depor keeper German Lux from 30 yards, and Diego Simeone's team remain in fourth spot in La Liga.
Griezmann, though, said he was concerned only with his teammate's condition.
"I don't really care now about football or the result," he told Gol TV. "We are only worried about Fernando's health at the moment. We hope he's OK and back with us as soon as possible."
ESPN FC's Dermot Corrigan contributed to this report.