West Ham boss Gianfranco Zola is still waiting to learn the extent of the injury suffered by Valon Behrami against Manchester City.
Behrami was stretchered off in obvious pain with his knee and ankle heavily strapped after catching his studs in the turf as he challenged Wayne Bridge.
Zola confirmed after the 1-0 victory that the midfielder had been taken to hospital to ascertain the full extent of the injury
The Italian told Sky Sports: "We are still waiting. He has gone to a hospital for the MRI.
"Hopefully it is not going to be too bad. We are very sorry for him, he is such an important player for us."
Behrami's replacement Savio played a major role in the winning goal, with his shot parried by Shay Given for Jack Collison to coolly lob home in the 71st minute.
Both men earned warm praise from their manager, with Zola particularly pleased with Collison's efforts.
He said: "Jack is unbelievable, he's getting better and better. He's 19 and he's playing nearly every week. He's got a very good attitude and he is going to get better and better.
"I feel very lucky to have him. Not only him but other players. That's why I like the attitude here.
"I can play them in different positions. As long as you know how to play football you can still produce and be important for the team. I'm sure I could play Jack Collison up front or right at the back and he could still produce good results for the team."
Savio, a club-record buy in January from Italian side Brescia, is another who is gradually making his mark on the Premier League and Zola was pleased with his game-turning cameo.
He added: "Savio has done well, the boy came on today and played a good game.
"I'm pleased for him because he came here with a lot of expectations and to be honest he was a little bit under pressure because he knows people are waiting for something special from him.
"But I'm pleased with how he is working and his attitude is good. He is going to be a successful player here I'm sure.
"We bought him because he has something different, something that is sometimes missing in a game and today we saw a little bit of that.
"I'm sure there's still a lot to come from him."