Shaun Pollock believes there is "a real possibility" AB de Villiers could retire from Test cricket after South Africa's series with England.
De Villiers revealed during the first Test that he was looking to ease his workload, although he quashed rumours he was set to quit the five-day arena.
However, former South Africa all-rounder Shaun Pollock feels De Villiers, who replaced Hashim Amla as Proteas Test captain after the second Test, may exit the longest form of the game as he strives to balance his work and home life.
"I think the possibility [that De Villiers quits Tests] is very real as the fantastic T20 player he is means he can command any fee he wants all over the world," Pollock told Sky Sports.
"He has been in a successful unit but when the team's not doing so well it's not as much fun and you start to think about those other options.
"He has just had a little baby, too, and time with the family is something he will be looking forward to, so it is a big worry for South Africa."
South Africa have been replaced by India - the team that thumped them 3-0 in the sub-continent prior to Christmas - at the top of the ICC Test Rankings after losing the series to England with a game to spare.
Kagiso Rabada's five-for in Johannesburg and Temba Bavuma's century in Cape Town were plus points for the Proteas, but Pollock feels De Villiers' side have a job on to arrest their slide.
"I think it's in decline, there's no doubt about it," added Pollock, who took 421 wickets and scored 3,781 runs in his 108 Tests for South Africa.
"We used to go away and people would say to me: 'your side is a very settled Test unit', as we knew where we fitted in, who did what role and where we were going to get our performances from.
"At the moment we don't know that - having Dale Steyn and Vernon Philander missing is a huge blow bowling-wise, while we have also lost a lot of experience in the batting department.
"Confidence is not oozing out of the dressing room and that is difficult to turn around, particularly when you have a lot of inexperienced guys looking to fill other players' shoes.
"There is a lot of work to be done."
See how South Africa fare in the final Test of their series with England in Centurion, from 8am, Friday, Sky Sports 2 HD.