24-year-old O'Donnell intially arrived in 2006 on loan from Liverpool where he made 25 league apperances during that season.
He then joined the Railwaymen in a £100k deal from Liverpool and during the last three seasons made 78 league appearances which included 27 league appearances this season.
26-year-old Schumacher arrived in 2007 for a fee of £10k from Bradford City and made 73 appearances in total for the Railwaymen netting 7 goals in the process. Schumacher's time has been blighted with niggling injuries and only made 27 starts this season and 5 from the bench although he has chipped in with 4 goals.
Dario Gradi told the official website 'Danny has done well during his three years as well, but it is probably better for both us and him as a player if he goes elsewhere.
'Steve is a goal scoreing midfielder and I would have liked to have kept him but he has suffered injuries during his time here and I'm hoping to have Ashley Westwood and James Bailey here next year still, and they are both ahead of him.'