Can i legally resign a fulltime job while out on sugical disability without reprocussions?

i recently found out i need surgery. i requested lightduty/non weight bearing assignments im getting a run around with administration. i am an rn working in all environments of the hospital. i am loyal/dedicated. have been suffering work related foot issues for > 1 year that require surgery with a recovery of 6-8 weeks non weight bearing. admin will not put in writing their verbal agreement for light duty/non weight bearing return to work.... any advice is appreciated