John Terry has dealt Chelsea a major injury scare after revealing he has cracked two ribs and is struggling to breathe during games.
Terry was due to undergo a scan on Thursday morning after coming off an hour into Wednesday's Champions League quarter-final second leg against Benfica.
The 31-year-old suffered the injury in last Tuesday's first-leg victory in Lisbon and was able to complete that match and play 90 minutes of Saturday's Premier League win over Aston Villa.
He revealed he was gasping for air on Wednesday night, but insisted he was ready to continue playing through the pain during what is a nightmare run of eight games in just 26 days, including Champions League and FA Cup semi-finals against Barcelona and Tottenham respectively.
"I couldn't breathe and my chest was closing up," he said on Wednesday night. "I was having a difficult time out there, especially in the first half. Hopefully, I'll be okay.
"I don't know how long I'll be out. I will have a scan in the morning and we will see where we go from there. It's just horrible.
"When you get one in the ribs, you can't do anything about it, you can't treat it, you just have let it heal, but I can get through games definitely. I thought it was okay but, later in the second half, it just seemed to be getting worse and I was struggling to breathe to be honest.
"It was difficult. I have never felt anything like that before."
Chelsea can ill afford to be without Terry for any length of time.
They struggled badly during his absence with a knee injury earlier this year and their remarkable turnaround in fortunes under caretaker manager Roberto Di Matteo also coincided with Terry's return.
It is unthinkable Chelsea could line up against Barcelona without their captain, who insisted his side were more than capable of upsetting the European champions after winning seven and drawing one of their last nine games.
Terry said: "It's a very good achievement to reach our sixth semi-final in nine years, but we want to go through to the end.
"Clearly, that's going to be tough against Barcelona, but we're playing well. I am not sure anyone will fancy playing us at the moment because we are a very good side, especially in this competition.
"Barcelona are a very good team, but home and away we're a very solid side as well. We have shown that away against a very good Benfica side and proved on big nights at Stamford Bridge that we can really upset teams as well.
"We're confident. It is important we keep this momentum because we're going well in the league. That is the key for us."
Gary Cahill came on for Terry on Wednesday and is confident of stepping into the breach against Barca if necessary.
The January signing from Bolton said: "I am ready to face them if selected. It is exciting to play against Barcelona. This is why I joined the club. If called upon to play in that game, it will be fantastic."