Do we need more unproven Championship standard centre backs?
15 games for West Ham in the Premier League, and 115 for Coventry (as well as a fair number loaned at Plymouth earlier in his career) suggests he is anything but unproven.
Most teams that are promoted never manage to sign Premiership proven defenders anyway, at least not ones at their peak. Steven Taylor, Coloccini, Williamson, Ward and one more decent backup (and Kadar) and I'd say that's decent enough in the CB position for going up next season.
EDIT: And obviously he fits Ashley's age policy (will be 25, probably the right age to give a 3-year deal to) and his money policy (free).