The Gunners take on their West London rivals in the second leg of the Carabao Cup semi-finals on Wednesday, 24 January, and Arsene Wenger had revealed earlier in his press conference that the duo were doubtful with tests planned for both of them.
The tie is finely poised after a 0-0 draw in the first leg at StamfordBridge but Chelsea will be without two key men for the return.
Arsenal secured the signing of Henrikh Mkhitaryan from Manchester United in a straight-swap deal involving Alexis Sanchez last night, but he is ineligible to feature, having participated previously in the Cup for the holders.
Courtois missed that game at the Falmer Stadium but is declared fit for this game and should start under the bar against Arsenal.
The replay follows a drab goalless first-leg that means the victor on the night qualifies for the final.
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Pressed on the nature of Morata's problem, he added: 'He has a problem in his back. "Then I have to check a couple of situations [in terms of injuries to other players]".
Defender Andreas Christensen will though be available after recovering from a head injury.
"The same in the EFL Cup, he only played 10 minutes". 'Every game is different, the opponents change and you must be intelligent to understand if it is right to continue in the same way with the same players'.
Stewart Robson analyses Chelsea's performance against Brighton, highlighting exactly why the centre forward position is so important for Antonio Conte.
"Tomorrow there is not another game and we don't have another possibility and we need to try to reach the final".
Azpilicueta, save perhaps for Eden Hazard, is Chelsea's most consistent and important player. "Arsenal, for sure, want to get there as well".