The England defender received the bad news yesterday when a hospital scan revealed a Grade Two tear.
It is likely that he will miss four to six weeks of action though he is determined to press ahead with plans for an oxygen tent in his house in a bid to speed his recovery.
“It is not what I wanted to hear at all,” lamented Richards. “I felt sick when I was told. I knew from experience when I did it that it felt like a bad one but I was hoping for the best.
“All I can do now is concentrate on getting back as quickly as possible. I must admit I did think ‘why me?’ for a while when I heard the news. Of all the games to miss a Wembley date with United is the last one any player would choose.”
Roberto Mancini’s defensive problems don’t end there as the current international break continues to take a terrible toll on his squad.
Germany’s Jerome Boateng has damaged his meniscus (knee) I training with the national team and could also be looking at a lengthy spell on the side lines.
Initial reports from the German camp suggested Boateng will need surgery but the Blues will seek a second opinion once the club’s own medical staff has made an assessment.
The injury is thought to be similar to one recently sustained by Mario Balotelli and the hope is that the defender may be able to avoid the operating table.
The dual blow and the absence of the suspended Kolo Toure leaves the Blues thin defensively.
Pablo Zabaleta is still away on compassionate leave in Argentina leaving youngsters Dedryck Boyata and Wabara Reece as candidates for a place in the side against Sunderland on Sunday.
Blues defender Nedum Onuoha, currently on loan with the Black Cats, is not allowed to play in the contest.
