The 22-year-old felt his hamstring in the warm-up at Burnley on Saturday, and was withdrawn from Chelsea’s starting line-up for the 3-0 Premier League win.
A scan at Chelsea’s Cobham training ground revealed no major damage.
“Christian had a scan that showed a minor injury,” said boss Frank Lampard.
“It’s obviously a relief for the injury to be minor because he’s an important player for us and he’s already back outside [training]. He won’t be fit for Wednesday, but we’ll see after that.
“He made the right decision in not attempting to play [against Burnley], as he could have made it worse.”
Chelsea are top of Group E after a 0-0 home draw with Sevilla, followed by a 4-0 away win over FK Krasnodar, while Rennes, third in France’s Ligue 1, are bottom of the table.
Goalkeeper Edouard Mendy, who joined the Blues from Rennes in September, could face his old club.
The Senegal international has only conceded one goal in his six games since the move, including five successive clean sheets.
“He has shown big parts of his game and made big saves in big moments,” said Lampard. “He has given off a sense of calm in his distribution and coming for crosses. It is early days for him at the club. I am very confident in him.
“When we were in to sign him all the feedback was he had a strong personality in the dressing room. He is very low maintenance. He wants to engage and works hard. He always has a smile on his face, he is a positive in the dressing room.”
- Chelsea and Rennes have never previously faced in any competition.
- Chelsea have lost just one of their nine home Champions League games against French sides (won five, drew three), a 2-1 defeat against Paris St-Germain in March 2016.
- Chelsea have only suffered one defeat in their previous 15 home games in the group stage of the Champions League (0-1 against Valencia last season), winning nine and drawing the other five games in this run.
- Chelsea are yet to concede a goal in the Champions League this season, while they last started a campaign with three consecutive clean sheets in the group stage in 2009-10, under Carlo Ancelotti.
- Timo Werner has been directly involved in 11 goals in his past 13 appearances in the Champions League (eight goals and three assists), including six goals in the most recent six (three goals and three assists).
- Hakim Ziyech scored his first goal for Chelsea in the Champions League on matchday two (against FK Krasnodar), while he could become just the third player to score on his first two starts for the club in the competition, after Didier Drogba in 2004 and Daniel Sturridge in 2010.
- Rennes have lost their two away European games in England – in August 2001, they were beaten 1-0 by Aston Villa in the Intertoto Cup, and in March 2019, when they lost 3-0 to Arsenal in the Europa League.
- Rennes have only kept one clean sheet in their past 12 games across all European competitions (2-0 against Lazio in the Europa League last season), conceding 18 goals in total in this run.
- Rennes are on a five-game losing streak away from home in major European competitions (excluding qualifiers), with four of the defeats in this run coming since the start of last season.
- Forward Serhou Guirassy has scored three goals in his past five games in major European competitions (excluding qualifiers), including his team’s only goal in the Champions League so far this season (against FK Krasnodar).
Entertainment data company Gracenote says Chelsea have a 97% chance of progressing to the knockout stages of the Champions League.
Simon Gleave, head of sports analysis at Nielsen’s Gracenote said: “Having drawn with each other and won their other match, Chelsea and Sevilla are huge favourites to go through from Group E.
“The Euro Club Index makes Sevilla the most likely to win the group as they still have their home match against Chelsea to come. Chelsea have 46% chance of ending the group phase on top of Group E.”