Stoke City assistant manager Billy McKinlay has left the Championship club by mutual consent.
McKinlay also worked under O'Neill with Northern Ireland and was part of David Moyes' coaching teams at Real Sociedad, Sunderland and West Ham.
Stoke are 12th in the Championship and will spend a fourth successive season in the second tier in 2021-22.
"We would like to take this opportunity to thank Billy for his work over the past 18 months and wish him every success for the future," the club said.