The 25-year-old midfielder only joined the Hammers last summer from Wigan, but he has a £3.5million release clause in his contract and has been linked with a move to Arsenal.
Diame insisted last week that he was "happy" at Upton Park but the speculation over his future continues and Allardyce admits the situation amounts to "total confusion".
But he said: "Diame is a professional. He is paid to play for West Ham United. I expect everyone to put the shirt on and play with a passion, with the ability and desire that they have got.
"He has had a long spell off with a hamstring injury and is only finding his feet again. My plan is that I am playing him because I hope and I believe he is going to be here after Thursday."
West Ham have recorded just one Premier League win in the last eight, and were thumped 5-1 at Arsenal last time.
Allardyce added: "We aren't comfortable by any stretch of the imagination, based on recent results.
"It is not good enough and the players' responsibility is to get more points on the board, starting Wednesday, to produce a result from the game and see if we can move on from there."