The defender was overlooked in the Italian's squad for the forthcoming friendlies at Wembley against Spain and Sweden despite his good-form helping Manchester City to the top of the Barclays Premier League table.
Richards - who became England's youngest-ever defender when he made his international debut under Steve McClaren in 2006 as a 17-year-old - has played just once since Capello took charge.
Disappointment: Micah Richards has played just once since Fabio Capello took charge of England
Fit-again Liverpool full-back Glen Johnson and Tottenham's Kyle Walker have been preferred in the England party and Richards responded on social networking site Twitter, saying: 'Well well well!!!! Disappointed is an understatement!!'
He then thanked City for their support, adding that he would continue to work hard to try and force his way back into the England reckoning.he posted: 'Just want too thank mcfc for being loyal to me throughout my career! Through the ups and downs. ctid!!!!!! I'll do anything for this club.
'Oh well better look (sic) next time! Roll the sleeves up and work harder! #cantstopwontstopdontstop'.
Stuck in: Richards insists he will continue to work hard for Manchester City
Richards' cause appeared to be championed by former team-mate Joey Barton.
The QPR man said on Twitter: 'Don't understand Eng (sic) Squad. No Newcastle players?? No Micah Richards?? Surely he has to be. Man City 5 pts clear, MoM at Old T and skipper??'
Speaking after City's 3-2 win over QPR on Saturday - a result that saw Roberto Mancini's men stretch their lead over rivals Manchester United at the top of the table to five points - Richards said he would relish the opportunity to be picked by Capello.
He said: 'I've still not been given a start under this England manager, so I've not been able to show what I can do.
'I know my form has to be right for City before he can pick me, but if he gives me my chance I am sure I can take it with both hands, just like I did before.
On the ball: Richards has the next week to train at Manchester City instead of linking-up on international duty
'Jones and Smalling have been doing well for Manchester United.
'If the manager wants to give them a chance it is up to him, there is no point in me moaning about it.
'I know what I've got to do - keep working hard - and that's what I'll do.'
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