Cape Town - AB de Villiers' decision to retire from international cricket is a massive blow to the Proteas, whichever way you look at it.
De Villiers, who will go down as one of the greatest the country has ever produced, leaves with an average of over 50 in both Test and ODI cricket.
The most obvious blow is to South Africa's chances at next year's Cricket World Cup in England.
De Villiers is one of the most destructive batsmen the game has ever seen and he has the ability to win matches by himself. He was considered a major weapon for the Proteas - probably their biggest - as they continue preparations for next year, but now they must get the job done without him.
De Villiers' absence will first be felt in the Test set-up, though, when the Proteas tour Sri Lanka next month.
Gibson and the Proteas brains-trust must now identify a new batsman in the all-important No 4 position.
That, historically, is where a side's best bats.
Steve Smith for Australia, Virat Kohli for India, Joe Root for England (up until recently). The reason the best bat at No 4 is because it is a position that requires a player talented enough to adjust to any match situation.
If a side loses two quick wickets then their No 4 needs to settle things down, but he must also be able to dictate the tempo of a Test through positive play when the situation commands it.
Looking long-term, we have identified a few guys who are options to fill the No 4 void.
Age - 28
Average - 34.87
This is the most logical fit. Proteas captain Faf du Plessis has spoken in the past about the possibility of Bavuma batting at No 4. He is a man rated highly by the Proteas brains trust, and bringing him in at No 4 would not disrupt those around him. Bavuma was the man left out when De Villiers made his return to Test cricket at the start of 2018, but now he will be given an opportunity for a long run in the side. The only issue here is that Bavuma has been a nice option at No 6, where he seems to gel well with the lower order. Is it worth taking him out of that comfort zone?
Age - 23
Average - 55.55
Markram has been sublime at the top of the order in 2018, and the obvious question here is why South Africa would tamper with a good thing. If he is making runs as an opener, then why move him down? The fact is that Markram is good enough to make runs wherever he bats, and if we go by the logic of having your best player at No 4, then he must surely come into that conversation. It probably won't happen, but the comfort that would come of having a player like Markram anchoring the middle order in the Test side for the next 10 years is hard to ignore.
Theunis de Bruyn
Age - 25
Average - 14.44
There was good news this week when De Bruyn was contracted to the Titans for 2018/19. It is time, however, for him to start delivering on the Test stage. His opportunities have been limited, and the Proteas need to give him an extended run in the Test side to settle and hopefully prove his worth. If they don't, the lure of deals abroad may come into play. Playing De Bruyn at No 4 would allow Bavuma to stay put at No 6, so it all depends on who the Proteas back more to get the job done higher up the order.
Faf du Plessis
Age - 33
Average - 43.20
Du Plessis seems more sold on the idea of Bavuma at No 4 than anyone else, but he might want to take on the added responsibility to protect those around him. There is no doubt that Du Plessis has the pedigree and experience, and stepping into the void left by De Villiers may be less daunting for him than his above-mentioned team-mates. Du Plessis has, after all, batted at No 4 on seven occasions for South Africa and he boasts a healthy average of 41.57 in that position.