Leicestershire's longest-serving player Ned Eckersley is one of four men who have not been offered new contracts by the club.
The 29-year-old wicketkeeper made his Foxes first-class debut in 2011 and has scored 5,646 runs at a 32.26 average.
Batsman Mark Pettini, all-rounder Tom Wells, and spinner Rob Sayer have also not been offered terms for next season.
Head coach Paul Nixon said it was an "extremely sad time of year" when tough decisions in planning had to be made.
"On behalf of the whole club, I would like to thank Ned, Tom, Rob and Mark for their efforts over the years, and wish them all the very best for the future," Nixon added.