Kent assistant coach Allan Donald will now take up his role in 2018 after delays to obtaining a work permit.
The former South African fast bowler has coached several Test nations and in the Indian Premier League but must complete his Level 3 coaching qualification before he can start his role.
In the meantime, the 50-year-old will take up an interim role with Sri Lanka Cricket during the upcoming Champions Trophy in England and Wales as visa rules only apply to UK employers.
Donald said: “I’m 100 per cent committed to Kent despite the frustration of not being able to join Matt Walker and the boys as planned.
“In the meantime, I’m working towards my Level 3 and this opportunity to work with Sri Lanka means I can return to coaching before joining Kent in time for next season.
“I’m following this season closely and hoping the boys can get promotion and compete in white-ball cricket.”
Head coach Matt Walker said: “It’s frustrating that a coach of Allan’s calibre and experience is unable to join us sooner but Jason Gillespie has slotted in superbly as our interim assistant coach.
“Jason will return to Australia midway through the season and we will announce a second interim coach to cover for Allan in due course.”