Sidwell was part of the Arsenal side that won the FA Youth Cup in 2000 and 2001 and had loan spells with Brentford and Brighton.
He was unable to force his way into the first team with the Gunners and moved to Reading in January 2003 on a four-and-a-half-year deal.
Sidwell played a big role in Reading gaining promotion to the top flight for the first time two years ago, but he rejected a new contract that summer and left the Royals on a free transfer to move to Chelsea in 2007.
Villa manager Martin O'Neill, meanwhile, could name Martin Laursen as captain in place of Barry, who is waiting to get the go-ahead to complete his switch to Anfield.
O'Neil said: "There are a number of people on the list and Martin Laursen would certainly be one of the names I'd be thinking about.
"He was terrific last season. There are a number of people who would want it but there are a number of people who are on my list who might not want it. I haven't discussed it yet.
"There are quite a few candidates at the club and perhaps others not yet at the club so that's something I'll look at further down the line."
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