Ravel Morrison has returned to parent club West Ham from Cardiff City on compassionate leave.
Brighton boss Sami Hyypia is weighing up a move for former France captain Alou Diarra.
The 19-year-old, a Republic of Ireland Under-21 international, made 19 first-team appearances for Lee Clark's side last season.
Reilly, raised in Birmingham, joined the Blues academy as a seven-year-old and made his first-team debut in the FA Cup win over Sheffield United in January 2012.
He scored his first senior goal at Huddersfield in January this year.