Kewell has been handed his marching orders by Liverpool boss Rafa Benitez, thus ending a tumultuous five-year stay on Merseyside.
And Slater is adamant that Serie A would provide an ideal change of pace for Kewell, who has lived in England ever since arriving at Elland Road as a teenager in 1995.
"It's quite interesting for Harry at this stage of his career where he's spent every football moment of his professional career in England," said the former Blackburn Rovers midfielder.
"As we know he's had a rocky road at Liverpool because of injury and maybe a new championship is a good move for him and a breath of fresh air. Harry moving into the Serie A will give him a new experience and give him more development of his already extraordinary footballing talents.
"We all know about Harry's talent, there's no doubt, it's just a question of him getting his body back battle-hardened and there's been signs of that (in Australia's World Cup qualifiers)."