Jeffers, Gray and Simek to leave Sheffield Wednesday; Doncaster Rovers release six
Etienne Esajas, Sean McAllister and Leon Clarke have also been released.
Irvine - whose side were relegated from the Championship on Sunday after failing to beat Crystal Palace in the survival decider - has offered two-year deals to goalkeepers Richard O'Donnell and Arron Jameson.
"I would like to wish those players who are leaving the best of luck for the future," said Irvine.
Doncaster Rovers manager Sean O'Driscoll has revealed that six players will not be offered contracts this summer, following the club's impressive second season in the Championship.
Strikers Paul Heffernan and Lewis Guy are on their way, along with defenders Sean McDaid and Charles Fisher, midfielder John Spicer and goalkeeper Ben Smith.
For the full story read Thursday's Yorkshire Post.