Eden Hazard was absent from group on return to training on Wednesday

Azpilicueta will have to wear a protective mask like Nemanja Matic's one

Cesar Azpilicueta suffered a cheek injury three minutes in at Crystal Palace

Cesar Azpilicueta will have to wear a protective mask after Fraizer Campbell's kick to his face left the Chelsea defender with a double fracture of his cheekbone.

The Spanish right back was in considerable pain after a challenge just four minutes into Sunday's 3-0 win at Selhurst Park but managed to complete the full 90 minutes.

Azpilicueta trained with the rest of Guus Hiddink's squad at Cobham on Wednesday but will require a mask before taking part in full-contact activity.

Chelsea's Cesar Azpilicueta suffered a double fracture to his cheek in Sunday's win at Crystal Palace

Crystal Palace striker Frazier Campbell accidentally connected with Azpilicueta with an early cross

As the ball heads into the penalty area, Campbell's boot collides with the Spanish defender's right cheek

Azpilicueta had to be seen to by Chelsea's medical team but he was cleared to play on after the early kick

Azpilicueta went on to play the full 90 minutes but he will require a protective mask for future matches

The injury came about as Campbell swung a boot to cross ahead of the scrambling defender, accidentally catching him with his follow through.

No foul was given, although play was eventually pulled back for Azpilicueta to receive treatment.

Hiddink reassembled his squad on Wednesday after two days off and while Azpilicueta was present, Eden Hazard was unable to join the rest of the group.

Hazard had to be withdrawn after 16 minutes at Selhurst Park with a groin strain and will miss Sunday's visit of Scunthorpe United in the third round of the FA Cup.

Gary Cahill, who failed to recover from an ankle problem in time for the Palace game, was part of Wednesday's session.

Nemanja Matic adjusts his protective face mask during Chelsea's 0-0 draw against Manchester United

Fellow midfielder Cesc Fabregas had to do the protective gear after a facial injury of his own last season

Azpilicueta will not be the first Chelsea player to don a mask. Nemanja Matic has worn one for the last month after fracturing his cheek and nose.

Gary Cahill, Ramires, Cesc Fabregas, Fernando Torres, Petr Cech and Demba Ba have all previously had to take the protective measure after facial injuries while at Stamford Bridge.

A masked Gary Cahill holds off a challenge from Crystal Palace's Connor Wickham at Stamford Bridge