The Trotters have made major changes to their first team and reserve squads, with Matt Mills and Craig Davies also leaving.
A couple of high profile first-team squad members have been allowed to leave, notably vice-captain Matt Mills and Wales forward Craig Davies, who have been heavily involved this season, as well as ex Leeds striker Jermaine Beckford, back up goalkeeper Andy Lonergan and former Republic of Ireland international Keith Andrews.
Beckford has been on loan at Preston for the second half of the season, and has helped the Lilywhites into the playoff final as they narrowly missed out on automatic promotion.
The Jamiacan international was a star for Leeds, scoring 84 goals in a five-year spell at Elland Road earlier in his career, and may now be offered a contract at Deepdale if Preston get promotion.
The Trotters also released a group of eight youngsters, with Chris Lester, Georg Iliev, Luke Woodland, Glenn Matthews, Ryan Sellers, James Ball, Carl Kennedy and Kieran Nolan all failing to earn new deals.
Lennon is talking to Premier League veterans Eidur Gudjohnsen and Emile Heskey over a new contract, with both players appearing regularly after signing midway through the season.
First choice goalkeeper Adam Bogdan and midfielder Darren Pratley are also discussing contract extensions at the Macron Stadium.