Onions’ Durham team-mate Dale Benkenstein is working as Natal’s “batting consultant” until the end of their domestic season.
That Onions has agreed to join them suggests he is not over-optimistic about being on the plane to Australia this winter. The South African domestic season runs from September to February. If he is, however, his international commitments will take precedence over a spell in Kwazulu Natal.
The Gateshead-born fast bowler has taken 51 County Championship wickets in nine Durham matches this season, and has consistently been the outstanding bowler on the circuit over the three campaigns since returning from a potentially career-ending back injury.
Despite that, Onions has only played once for his country since, in a dead-rubber against West Indies in June 2012.
He was in the squad for three of the first four Ashes Tests of the summer and might well have featured in the fifth had he not broken a finger playing for Durham in Scotland.
To have only made nine Test and four one-day internationals appearances is scant reward for the 31-year-old’s talent.
As well as taking a senior squad to Australia, England also have a Lions tour there, theoretically doubling the chances of Onions being involved.
But some in the England management have doubts about his ability to take second-innings wickets and they are likely to prefer taller fast bowlers such as Stuart Broad, Chris Tremlett, Steven Finn and Boyd Rankin on the harder, bouncier pitches which are sure to await them in the second half of what is effectively a ten-Test mega-series.
As recently as Wednesday Onions was describing it as “a tour I’d love to be involved with” and on the announcement of his signing he was quick to stress “My availability (for Natal) will obviously depend upon England selections.”
It was on tour in South Africa that Onions started to establish himself as a Test-match player in 2009-10 before the stress fracture which saw him miss the entire domestic season.
“I am looking forward to playing in South Africa which is renowned as having one of the strongest domestic set-ups in the world,” said Onions.
Natal chief executive Jesse Chellan added: “Graham is contracted for the full season and will play in all three competitions (pending non-selection for England).
“He will add experience and know-how in leading the Sunfoil Dolphins attack.”
And their head coach Lance Klusener added: “Graham is an ultimate professional that will bring quality and experience.”
Durham’s next opponents, Derbyshire, will go into the game on the back of three wins out of four after none in their first 10 matches of the season. Former Riversiders Shivnarine Chanderpaul’s 74 not out saw them to a two-wicket win over Somerset, who have taken their place in the relegation zone.
The game at Derby, which starts on Wednesday, is the first of three between now until the end of the season for in-form Durham, who are 14.5 points clear at the top of Division One.
They finish with games against Nottinghamshire – still not safe from relegation – at home, then Sussex away. Second-placed Yorkshire play Sussex (away), Middlesex (home) and Surrey (away). For Durham to be in contention after a year beset by problems is a fantastic achievement in itself.
Captain Paul Collingwood said: “I’m very, very proud of the guys and where we’ve got so far.
“We have got an opportunity, there’s no pressure on us whatsoever because there was nothing expected of us at the start of the season.
“We’ll just go about our merry way and try to win games.”