Chelsea's 100% record under Maurizio Sarri came to an end as they had to settle for a point at the London Stadium.
But if the German is not ready to face Liverpool on Saturday, Langley says Cahill must be the man to step in at Anfield; he has fewer concerns about the EFL Cup game between the two teams on Wednesday.
With West Ham sitting deep, it was hard for Chelsea to play the intricate, one touch football - known as "Sarri-ball" - demanded by their manager, and Giroud felt they needed to try something different. We have played only six matches.
Sarri talked about the need to move the ball more quickly and create better movement off the ball following the 0-0 draw at the London Stadium. "Against a team who have worked with the same coach for three or four seasons".
Needing a two-goal win to depose Liverpool at the top of the table, Chelsea struggled to make clear chances despite having the majority of possession and stayed third behind the Merseysiders and champions Manchester City.
"We have started to work all together 35, 40 days ago".
"They will provide a real test of how good we are", the striker told the London Evening Standard.
"Maybe I will have to change 11 players, maybe five, I don't know".
"I said only that I don't know why, in England, after an away match in the Europa League to play in the Premier League on the Monday night".
Chelsea finished the half with a flourish, but N'Golo Kante's header from Willian's cross went just wide.
"They were cutting out very well every pass for [Olivier] Giroud, so we needed two wingers, I think. Maybe then I have to rest many players on Thursdays. five, six, seven at a time". I am surprised. In Naples, the first month was very hard.