Cape Town - Kent admitted that they are frustrated over the issues preventing former Proteas Allan Donald from taking up his role with the English county.
Donald, 50, was appointed as assistant coach in January, but will now take up his role in 2018.
The former Proteas fast bowler has faced delays in obtaining the necessary paperwork as he did not hold the correct coaching qualifications - the English Cricket Board (ECB) criteria of a Level 3 coaching qualification.
Donald has coached several Test nations including the England national team and gave his bowling expertise to the Royal Challenges Bangalore in the Indian Premier League this season.
He has since taken up an interim role as bowling coach for Sri Lanka Cricket ahead of the ICC Champions Trophy in England - as visa rules only apply to UK employers.
"I'm 100 percent committed to Kent despite the frustration of not being able to join Matt Walker and the boys as planned," Donald told the English county's website.
"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."
Kent's head coach Matt Walker said he was disappointed that Donald's visa issue could not be resolved before the start of the County Championship or their One-Day Cup season.
"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," said Walker.
"Jason will return to Australia midway through the season and we will announce a second interim coach to cover for Allan in due course."
Donald, who was one of the greatest fast bowlers of his generation, had spells as a player in English cricket with Warwickshire and Worcestershire.
Donald played 72 Tests and took 330 wickets, and played 164 ODIs for the Proteas with 272 wickets.