When pages of an index for a data-only-locked table are marked as suspect during recovery, the entire index is taken offline.
sp_listsuspect_object
sp_forceonline_object
In most cases, a system administrator uses sp_forceonline_object to make a suspect index available only to those with the sa_role. If the index is on a user table, you can repair the suspect index by dropping and re-creating the index.
See the Reference Manual: Procedures.