The French international was expected to be ruled out for six months after sustaining the injury in a Capital One Cup clash with Cheltenham, but came through 90 minutes of reserve-team action earlier this week.
Now Diarra, who joined the Hammers in 2012 and spent most of last season on loan at Rennes, believes he is closing in on a first-team recall which will provide a timely boost to boss Sam Allardyce's options.
Diarra wrote on the club's official website: "I will train hard every day to try to play in the Premier League. Maybe I will be involved against Chelsea. I hope I will be ready but it is up to the manager.
"I am not feeling 100 per cent just yet but my knee is feeling stable and stronger. With every training session I will get better and I am happy to be playing because it was eight hard weeks.
"I was very unlucky because I did a good pre-season but football is like that. I must accept my injury and I have worked hard to come back. Now I'm on the pitch and I am available for the team."