Reece James will miss Chelsea's trip to Leicester City on Saturday through illness, but boss Graham Potter is hopeful N'Golo Kante will make his long-awaited return next week.
James has endured a frustrating few months, making just 11 Premier League appearances this season and missing England's World Cup campaign after suffering a knee injury ahead of the tournament.
The wing-back missed last Saturday's 1-0 win over Leeds United with a hamstring issue, though he returned as Chelsea overcame a Champions League last-16 deficit to eliminate Borussia Dortmund on Tuesday, easing the pressure on Potter.
The latest setback to befall James will see him sit out Chelsea's trip to the King Power Stadium, while fellow England international Raheem Sterling is also a doubt.
"Reece has been ill and he's not trained today, so he won't make the game tomorrow," Potter explained at Friday's pre-match press conference.
"Raheem had a feeling in his hamstring, more tightness than anything, so he's looking doubtful for tomorrow as well."
Six of Chelsea's nine Premier League wins this season have come in the 11 games in which James has featured. The Blues have won just three of their 14 matches without the 23-year-old.
Chelsea count the likes of Kante and Thiago Silva among their more long-term absentees, with the former last featuring in August's 2-2 draw with Tottenham after suffering a hamstring injury and the latter aiming to return in April from a knee problem.
While Potter ruled out Kante returning against the midfielder's former team, the Blues boss revealed next week's home clash with Everton was a realistic target.
Asked whether Kante would be available at Leicester, Potter said: "No, he won't. He still needs some more time to build up. We're aiming more towards Everton, but unfortunately it won't be tomorrow.
"The most important thing for [Kante and Silva] is to get them back injury-free. The more good players we have, the better."
Chelsea's back-to-back victories have gone some way to easing pressure on Potter, after he watched his team win just one of their first 11 matches of the calendar year.
Asked if he felt a weight had been lifted in the last week, Potter said: "Yeah, in some way. It's always nicer to win, it's as simple as that. Everything feels a bit better, like you've taken a step forward.
"But I'm not getting carried away, it's just two wins. We have to focus on Leicester. The boys have stuck together through a bad time, and there's a lot to be said for that.
"The supporters have been really fair. Results-wise we haven't done that well, so you understand the criticism.
"It's hard for them to get behind something when the results aren't something to get behind. I have nothing to say about how we've been treated by the supporters, they've been great."