Even if he recovers from his back injury, Morkel's career is on the wane at the age of 32, and he may consider the tour of England to be his last hurrah. Morkel has not played for South Africa since June and lost ground to Abbott in that time, although he should find himself in contention for a Test spot when fit, especially after du Plessis stressed the importance of experience in the longest format. But the same may not apply in other formats. Morkel played just one of the six ODIs in the Caribbean triangular in June and was not included in the World T20 squad, which suggests South Africa are starting to move on.
A tale that is almost Abbott-like in that de Lange made a stunning first impression when he took 7 for 81 against Sri Lanka on debut in 2011, but has struggled for opportunities since. However, the fact that he lacks Abbott's consistency heightens the sense that he may be tempted to look elsewhere. He has played just two Tests and 10 limited-overs matches since bursting onto the scene and the frustration could be creeping up on him. A stress fracture and remodelled action stalled some of his progress and he has struggled to maintain a regular place at the Titans' franchise as well as internationally. He relocated to Bloemfontein ahead of this summer and, at the halfway stage of this season's first-class competition, was fourth on the wicket-taker's list and bowling with pace once again.
A Test cap is probably not in Miller's future, which may prompt him to look elsewhere if he is not satisfied with his lot as a white-ball specialists. He went 16 innings without a half-century in 2015 and was left out of the touring party for the triangular series in the Caribbean last winter, but recalled to play against Australia in October. What may encourage him to stay is that he is part of South Africa's Champions Trophy plans, and very much in the running for the 2019 World Cup as well. Plus, he has a massive IPL contract that is said to be in the range of R25 million (US$1.82 million). CSA have also been willing to release him to other tournaments such as the CPL.
Another nearly-man, Morris played two Tests for South Africa against England early in 2016 but has since fallen off the long-format radar and is not a certain pick in white-ball cricket either. He went to the World T20 and last played ODI cricket in June 2016, before suffering a knee injury in September which sidelined him almost four months. He missed the ODIs against Australia as a result. The niggle could not have come at a worse time because Morris was establishing himself as South Africa's lower-order finisher and will now have to fight to get that place back. He was due to make a comeback for the Titans in a first-class fixture against the Knights this week, but that match has yet to get underway because of rain.
Picked as the first-choice wicketkeeper for South Africa's Test tour to India in last 2015, Vilas became one of the casualties of what was a disastrous visit. South Africa lost 3-0 and their batsmen were outspun on turning tracks. Vilas only made 60 runs in seven innings and was promptly replaced by Quinton de Kock on the team's return. He travelled to Australia as a reserve gloveman but has admitted his chances of a recall are slim. He is a strong candidate for a Kolpak option, taking into consideration his age (31) and his career prospects. Vilas is a senior player at the Cobras' franchise but does not play in any T20 leagues. A county deal may suit him best.
Pretorius has only played three ODIs to date but, with Abbott no longer on the scene, he has a chance to add to his caps quickly. Players need to have appeared in at least 15 white-ball internationals in the past two years to be considered for a Kolpak deal. South Africa have four T20s and ten ODIs in their schedule before the end of March. He will compete for a place as one of two allrounders with Andile Phehlukwayo and Wayne Parnell and so may find it difficult to get a regular run. Pretorius travelled a long road to become an international cricketer and it may be too early in his international career to think of a Kolpak deal, which makes it even more important that CSA ensure he is given enough opportunity to succeed.

And a couple more worth keeping tabs on

Neither Theunis de Bruyn nor Duanne Olivier have played any international cricket yet but they are both on the cusp. De Bruyn is in the current squad for the Sri Lanka Tests as a reserve batsman and Olivier was added to replace Abbott for the third Test at the Wanderers. With the batting line-up settled, Olivier is the likelier of the two to debut there, but South Africa will think hard about whether they want to cap him just yet, given that they are unsure if he will get a long run.
Coach Russell Domingo expressed reservation over handing out new caps if there is the chance of the player using it as a ticket to the UK. "So if Kagiso Rabada breaks a finger tomorrow and I ask Duanne Olivier to come and play a Test match, but bear in mind that Kagiso is coming back straight afterwards because he's one of the best bowlers in the world, Duanne might say, 'Well stuff that, when am I going to play again? I'm going to go and sign a Kolpak," Domingo said.
De Bruyn and Olivier, and later players like Aiden Markram and Wiaan Mulder, could prove key tests of how South Africa handles the current exodus. They have already lost five recent Test caps to Kolpak deals, robbing them of options for the national side and depth in domestic cricket. The plans they put in place to keep these players will be crucial to South Africa's cricketing future.

Firdose Moonda is ESPNcricinfo's South Africa correspondent