Millwall have released Shane Lowry, Andy Keogh, Liam Feeney and Jack Smith as they begin their planning for next season.
Ian Holloway guided Millwall to Sky Bet Championship safety on the final day of the season and the aforementioned quartet were all out of contract this summer.
A club statement read: "The club would like to place on record its thanks and gratitude to the quartet for their efforts whilst at The Den, and wish them all the best for their future careers."
Simeon Jackson, who joined the club on a short-term deal in January, is also expected to be released.
However, Jermaine Easter has signed a new one-year contract while Lee Martin and David Forde are discussing terms over new deals at the Den.