Arsène Wenger revealed the news in an exclusive interview with Arsenal TV Online on Thursday afternoon.
Hleb's absence was already known. On Wednesday he received a suspension for the final three games of the season following an incident in the game against Reading last Saturday, meanwhile Rosicky has not played since January because of a hamstring problem. However news of Diaby's injury was acutely disappointing.
The Frenchman ruptured a tendon in his thigh in a Reserve game on Monday night. Wenger believes his recuperation will take eight weeks and that will be a body blow to Diaby's chances of being selected for Euro 2008. Ironically, the 21-year-old was due back from a domestic suspension at Derby on Monday.
Elsewhere, Bacary Sagna and Mathieu Flamini (both ankle) are still out. Manuel Almunia is fit after his wrist injury but the manager has yet to decide whether the Spaniard will return for the trip to Pride Park.
"It looks like the season is over for Hleb, Rosicky and Diaby," said Wenger. "Hleb is suspended and I don't believe we'll see Tomas Rosicky again [this term].
"But we have lost Abou Diaby too. He was supposed to come back after suspension but he got an injury that will rule him out until the end of the season.
"The problem occurred during a Reserve game. It was a simple pass and he ruptured the tendon in his thigh muscle. It will be at least eight weeks for him.
"Almunia is available again but I have not decided what I will do with the goalkeepers yet."
Arsenal TV Online subscribers can see the full interview on Friday morning. In it, Arsène Wenger talks about:
- The Champions League Semi-Finals
- Why Arsenal did not sign Yaya Toure
- Stories linking Alex Hleb with Inter
- The latest on Mathieu Flamini's situation
- What has gone wrong for Derby
- Using 'Carling Cup' players for the run-in
- Seeing out the final few games