Thiago Silva and N'Golo Kante have both been left out of Chelsea's travelling squad for Tuesday's Champions League opener against Dinamo Zagreb.
Manager Thomas Tuchel has already predicted Kante could be out for a while after suffering a muscle injury during the 2-2 draw with Tottenham, although Silva's absence comes as more of a surprise.
The 37-year-old captained the side and played the full 90 minutes of Chelsea's 2-1 win over West Ham, in which he put on an impressive showing, but he will play no part in Tuesday's game against Zagreb.
Tuchel is expected to explain the duo's omissions in a press conference later on Monday.
Notable inclusions in the squad are Deadline Day arrivals Pierre-Emerick Aubameyang and Denis Zakaria, both of whom could make their debuts for the Blues if they make it onto the pitch.
Aubamayeng had been in Milan to be fitted for a mask to protect a broken jaw suffered during a home invasion, and his inclusion in the squad suggests he is now ready to play for his new side.
Young midfielder Carney Chukwuemeka has also travelled with the squad, as has right-back Reece James, who signed a new six-year contract with the Blues earlier in the day.