Chelsea manager Thomas Tuchel admits he's concerned about Thiago Silva.
The German confirmed Silva had suffered a muscle injury during Thursday's win over Tottenham.
Asked about Silva, Tuchel said: "I saw Thiago with a big strap around his muscle but we have to wait.
"It's worrying because it's a muscle injury."
Tuchel will be sweating on Silva's fitness after the 36-year-old played a key role in Chelsea securing three consecutive clean sheets.
Kurt Zouma is also sidelined with injury and could miss Sunday's clash with Sheffield United.
