Haddin was named as the vice-captain in an inexperienced 16-man party for this summer's series, in which only five of its members have previously played an Ashes Test match in England.
Inverarity is adamant that Haddin will help take some of the responsibility off the shoulders of captain Michael Clarke.
"We feel it's important to have a senior, seasoned player support Michael [Clarke] at this time," Inverarity told BBC Sport.
"When Shane Watson advised of his decision to stand down, the NSP (national selection panel) viewed Brad as the exceptional candidate to step into this leadership void."
Australia released their full squad for the Ashes on Wednesday.