John Terry has revealed that he was injured during Chelsea's Champions League quarter final second leg match with Benfica, with the skipper admitting he doesn't know how long he'll be unavailable for.
Terry was on the pitch for 59 minutes before coming off for Gary Cahill during the week, as the Blues moved through to the Champions League semi-finals.
And the club are currently fearing the worst for their captain, who admitted that he had trouble breathing while on the pitch.
"I couldn't breathe and my chest was closing up," the Chelsea star told Sky Sports. "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.
"In the away leg, after about 20 minutes, I got an elbow in the ribs and they sort of fear I fractured two ribs, so I've just got to wait and see the result of the scans.
"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."
Terry is famous for his toughness and ability to play through pain. The former England captain has endured setbacks both on and off the pitch before, and will need to use that strength as Chelsea face a particularly difficult schedule of eight games in 26 days.
Chelsea will need to work hard as a squad to balance their Champions League and Premier League commitments, and Terry hopes that they can finally win their first top-tier European trophy this season.
"It's a very good achievement to reach our sixth semi-final in nine years, but we want to go through to the end," he explained.
"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."