Chelsea boss Jose Mourinho says Romelu Lukaku's attitude was the reason he let the striker move to Everton.
Southampton fans finally have reason to cheer after signing Chelsea full-back Ryan Bertrand on a season-long loan.
Hackett, 29, made 145 appearances for the Lions, scoring five goals, since joining from Hearts in 2006.
However, he slipped out of the first-team picture this season and ended the campaign on loan at Wycombe.
Former Leicester and Watford full-back Stewart, 30, endured an injury-hit season since he signed last summer and managed just seven appearances.
Youngsters Jake Gallagher and Conor McLaren have also been released.