In the wake of the country's Rugby World Cup success several of the leading players have taken up overseas contracts.
Human told Netwerk24, "I think all our teams, with the exception of the Stormers, will lose a lot of key personnel. You are going to be left without experience in Super Rugby and that's why the Lions want to contract a guy like prop and former Springbok Jannie du Plessis.
"Every teams needs hard, experienced campaigners. With all the experience lost, 2020 will be a challenging season for the South African teams," he said.
Human's Bulls have been the hardest hit.
They have lost first five-eighths Handré Pollard (Montpellier), centre Jesse Kriel (Japan), lock Lood de Jager (Sale), lock RG Snyman (Japan), No 8 Duane Vermeulen (Japan), lock Jason Jenkins (Japan) and hooker Schalk Brits (retired).
At the opposite end of the scale the Stormers appear least affected.
They have lost second five-eighths Damian de Allende (Japan and Munster) and lock Eben Etzebeth (Toulon).
Missing from the Lions are: Malcolm Marx (Japan), flanker Kwagga Smith (Japan) while No 8 and captain Warren Whiteley will miss the season due to a possibly career-ending injury.
The Sharks will be without: Tendai Mtawarira (retired) and Coenie Oosthuizen, Akker van der Merwe and Jean-Luc and Dan du Preez (all going to Sale).
Media reports in South Africa said Whiteley definitely won't play for the Lions in next season's Investec Super Rugby competition.
Whiteley, who was unable to play in South Africa's Rugby World Cup success this year has continued to struggle with a knee injury that kept him out of action for much of the 2019 season.
Lions chairman Altmann Allers told Netwerk24, "Warren admitted to me he's still experiencing a lot of pain [in his knee]. It's a case of him recovering nicely, only to suffer setbacks and he won't be able to play any time soon.
"The decision was made that he won't be involved as a play for us in Super Rugby next year."
The knee injury is just the latest in a string of injuries in the past two seasons. But it is the knee ligament injuries of the moment that could end his playing career.
It is expected he may move into coaching and could have a role as a Lions forwards coach.
Under his leadership the Lions played in three consecutive Super Rugby finals and he also made an impact as Springbok captain. He played 23 Tests for the Springboks between 2014-18.
The Lions open their Super Rugby season against the Jaguares on Saturday, February 1.