Goalkeeper Petr Cech took part in training on the eve of the Champions League semi-final second leg with Atletico Madrid a week after being ruled out for the season by manager Jose Mourinho with a dislocated shoulder sustained in the first leg.
Cech departed after 20 minutes of last Tuesday's first leg, which finished 0-0, to be replaced by Mark Schwarzer with Mourinho subsequently ruling his number one out for the rest of the campaign, but it remains to be seen if the Czech has made a surprise recovery.
Captain John Terry (ankle) was also present in training, having initially been ruled out up to the May 24 final in Lisbon, while Eden Hazard (calf) and Samuel Eto'o (knee) were also present after recent absences.
It is not unheard of for an athlete to make a quick recovery from a dislocated shoulder as it depends on the tissue damage surrounding the injury.
It would still be regarded as a risk if Mourinho, who suggested Cech would require an operation, selects the goalkeeper.
Cech strode out to the training field at Chelsea's Cobham training ground while bouncing a ball with each hand. He warmed up with the full squad before breaking off with the goalkeepers, as usual.
As Schwarzer, Hilario and Mitchell Beeney continued their specific drills, Cech moved out of view of the media invited to the first 15 minutes of the session.
Central defender Terry missed last Sunday's win over Liverpool which keeps Mourinho's Blues in Premier League contention, albeit with the title destination out of their hands.
Playmaker Hazard was injured in the second leg with Paris-St Germain and striker Eto'o missed the first leg at Atletico with a minor knee problem.
Hazard has been Chelsea's most important attacking player this season, while Eto'o has scored all 12 of his goals at home.
Eto'o, like Mourinho, is bidding to win the Champions League with a third club, having already lifted the trophy with Barcelona and Inter Milan.
The availability of any of the quartet would provide a major boost for Mourinho, who is without suspended midfielders Frank Lampard and John Obi Mikel as well as ineligible pair Nemanja Matic and Mohamed Salah.
Whoever is fielded in goal - and Cech's participation in training could be a classic Mourinho diversion tactic - Chelsea need the defensive reinforcement skipper Terry would provide.
Terry could come in alongside Gary Cahill, with Ashley Cole dropping out for Cesar Azpilicueta at left-back and Branislav Ivanovic at right-back, reuniting Mourinho's preferred back four against Atletico and Diego Costa, the Spain striker who is reportedly Chelsea's main summer transfer target.