Niall McCusker had groin surgery in Germany earlier this week
Niall McCusker will miss Derry's Ulster SFC tie against Monaghan on 24 May while Sean Marty Lockhart is a major doubt with Mark Lynch also a concern.
McCusker had groin surgery in Munich earlier this week and Derry officials are hoping that he will be in contention again in around six weeks.
Veteran defender Lockhart has been unable to take a full part in training because of an ankle injury.
Lynch is also receiving treatment in the run-up to the Celtic Park game.
Banagher club-man Lynch missed the majority of the National League following shoulder surgery in the winter.
He did star in the National League win over Donegal in early April and then lined out against Kerry in the league decider a couple of weeks later.
However, Lynch has missed recent club games and did not take a full part in training on Tuesday, prior to the county's championship press night.
Derry manager Damien Cassidy has announced a 35-man championship panel which has a number of changes from the National League squad.
Joe Keenan returns after being left out of the National League panel while Ballinascreen's Carlos McWilliams and Slaughtmanus' Gavin McShane are also called up.
McShane did play during the McKenna Cup in January.
Lavey's Cailin O'Boyle and Danny Mulholland are also included with injured duo Paul Bradley and Colin Devlin both unavailable.
Ryan Dillon and Joe O'Kane are also missing after being part of the NFL panel.
Derry championship panel: Shane McGuckin, Barry Gillis, John Deighan, Sean Marty Lockhart, Kevin Mc Guckin, Dermot Mc Bride, Niall Mc Cusker, Kevin Mc Cloy, Carlos Mc Williams, Joe Keenan, Gerard O'Kane, Brian Og McAlary, Chrissy McKaigue, Paul Carton, Barry McGoldrick, Sean Leo McGoldrick, Patsy Bradley, Fergal Doherty, Joe Diver, James Conway, Enda Muldoon, Gavin McShane, Paul Murphy, Enda Lynn, Brian Mullan, Paul Young, Barry McGuigan, James Kielt, Cailin O'Boyle, Eoghan Brown, Eoin Bradley, Mark Lynch, Seamus Bradley, Paddy Bradley, Danny Mulholland