Seamer Tony Palladino has left Derbyshire after 10 years at the club.
The 37-year-old took 374 wickets in 146 matches across all formats to become the club's leading first-class wicket-taker of the 21st century.
Derbyshire's head of cricket Dave Houghton said Palladino was "a master of his craft".
"On behalf of everyone at Derbyshire, I would like to thank Tony for his performances and longevity with the club," Houghton added.
Houghton said Palladino's contract was not renewed as Derbyshire focus on promoting younger talent.
"We have given opportunities to a number of young bowlers this season and they've performed well across first-class and one-day cricket," Houghton said.
"They've proven they are ready to compete at a professional level and we want to continue to see that talent progress, ultimately meaning that there will be no place for Tony next summer."