The former Bath and England lock began a second spell at Sixways last May, working with then-head coach Richard Hill.
Hill departed earlier this season, though, and Worcester are now under the control of new rugby director Dean Ryan.
Ryan made his first appointment on Friday when Shane Howarth was confirmed as the club's new backs coach.
"Nigel is an experienced and dedicated coach who has worked tirelessly throughout his time at Sixways to develop the forwards," Worcester's rugby committee chairman Bill Bolsover said.
"However, under the guidance of our new director of rugby we are now looking to appoint a new-look coaching team.
"I would like to place on record our sincere gratitude to Nigel for all his efforts, and wish him well for the future."
Redman added: "Dean has been open and honest with me since his arrival and wants to work with people he knows.
"I understand that decision, and I wish the club the very best for the future as I look forward to my next challenge in rugby."
- Sports & Recreation
- Shane Howarth