John Terry gave Chelsea a major fright today after limping out of the club's open training day at Stamford Bridge.
Thousands of watching Blues supporters had their hearts in their mouths when Terry hobbled out of a practice match towards the end of the 90-minute session and went down clutching his right ankle.
The Chelsea captain failed to respond to on-field treatment and had to be helped from the pitch by two club medics, looking in some distress as he disappeared down the tunnel.
Fears were immediately raised over the 31-year-old's fitness for Thursday night's crucial Barclays Premier League game at Tottenham but the Blues quickly allayed those following further treatment.
Terry's problem was diagnosed as an Achilles tendon tweak suffered when he blocked a shot, with the club having no doubt he would be available for the trip to White Hart Lane.
His absence would have left Chelsea with only one fit centre-half in Branislav Ivanovic, with David Luiz also missing today's session with the knee injury that saw him sit out Saturday's 1-1 draw at Wigan, and Alex banished from the squad after submitting a transfer request.
Luiz and midfielder Ramires, who was also unavailable for the trip to the DW Stadium due to a bruised leg, continued to receive treatment on their injuries this morning, the club optimistic both would be fit for Thursday.
Terry's injury provided a dramatic end to the open training day, which gave supporters their first chance to see manager Andre Villas-Boas put his side through their paces since he took charge this summer.
Around 2,000 fans - many of them youngsters - looked on from Stamford Bridge's West Stand, with the remaining 3,500 who applied for free tickets staying away possibly as a result of the cold weather and forecast of heavy rain.
Villas-Boas had been keen to open up one of his training sessions to the media and public following recent criticism of his tactics.
But he understandably gave little away today amid the usual mix of warm-up routines and shooting practice, although there was an interesting small-sided game involving six miniature goals prior to the main practice match, which itself was played on a half-sized pitch.
The players departed at around midday to attend the Christmas party of their young supporters' group, Bridge Kids, before spending the rest of the afternoon visiting patients at a local hospital.
Tomorrow, it is back to business for a side who spoilt much of their good work in becoming the first team to beat Manchester City in the league this season by throwing away two points at Wigan.
Chelsea could find themselves 12 adrift of City by the time they kick off on Thursday but the in-form Daniel Sturridge has branded anyone who writes Chelsea out of the title race as "stupid".
The striker, who became the club's top scorer this season with goal number nine on Saturday, told their official website, www.chelseafc.com: "There are still five months to go and people would be stupid to assume we're out of the title race.
"We will fight to the last game. These sort of draws are upsetting because we worked so hard only to concede at the end.
"But we will work harder in training to be ready for the next game.
"It is frustrating for everyone and it is important we bounce back, which we will. Any team in the top six can win it. We're one of them."
Meanwhile, midfielder John Obi Mikel has become the latest Chelsea player to express frustration over his recent lack of games.
But the 24-year-old, who lost his place to Oriol Romeu after last month's 2-1 home defeat to Liverpool, insisted he would not complain as long as the Blues kept winning.
"It has been hard but the most important thing is that the team keep doing well," he said.
"As much as I want to play, the team come first.
"If the team keep winning then I shouldn't complain. Any time I am called upon, I just want to help the team win."