Chelsea could be without Diego Costa, Oscar and Nemanja Matic for the visit of West Bromwich Albion on 13 January, due to picking up injuries. Costa and Oscar were replaced during the FA Cup third-round win over Scunthorpe United, while Matic was an unused substitute for the game at Stamford Bridge.
Oscar was replaced by Ruben Loftus-Cheek at half-time in the 2-0 win, with the England Under-21 international going on to score his first Blues goal in the second period. Costa limped off from the field in the 86th minute after scoring the opener against the League One opposition, with Bertrand Traore coming on in his place.
Matic, meanwhile, was named on the bench despite suffering from mild concussion after a ball hit him on the head during a pre-match training session. The separate injuries make each player a doubt for the resumption of Chelsea's Premier League campaign against Tony Pulis's Baggies this week.
"Matic was injured in training yesterday [Saturday 9 January]," Hiddink told a post-match press conference, according to the official Chelsea website. "A goalie threw the ball at the back of his head from five or six yards away by accident. Yesterday he was a little bit dizzy and this morning too but I was glad to see this afternoon he was better.
"Oscar had a little problem with his toe. He had a small inflammation which was very painful. Nevertheless we would have taken off two or three players to bring youngsters on in the second half."
Meanwhile, Costa was described as "doubtful" for the game, according to The Express, by the Dutch coach, after he came off late on. The news regarding the Spain international is a particular blow, given his return to form since the departure of Jose Mourinho, with four goals having come in his last three appearances. It could leave Hiddink without a recognised senior centre forward.
The injuries could force Hiddink into looking to the Chelsea academy to supplement his first team, after Loftus-Cheek made a triumphant substitute appearance in the cup win. The 19-year-old converted from Cesar Azpilicueta's cross and Hiddink says he is willing to given youngsters further opportunities.
"It's difficult to rest a lot of players but we brought some youngsters on in the second half," he added. "That's good for them. It's difficult to know when to bring them on because you don't want to give them too much responsibility for a result when they are in this stage of this career but I'm happy with their performances.
"I knew their names before but I didn't work with them on a daily basis. Now I am starting to know them better and you see the possibilities they have and what they have to work on.
"Ruben came on and scored a beautiful goal not just in the execution but in the way he prepared himself for that goal. If you play a midfield with one controlling defensive midfielder and two running players he can play on either side. If you play two controlling midfielders, he can play higher up the field."