Eathorne and medium-pace bowler Michael Rae have been offered the last two Otago contracts.
They will join a settled-looking squad. For both players, the contract offer is a bit of cricketing lifeline.
Rae has slipped down the pecking order after a tough season with injury and form, while Eathorne might have thought he had exhausted his last opportunity.
The 30-year-old made his first-class debut in March, 2005. He played five games during his first two seasons but fell out of favour until he made a surprise return last summer.
He has also played seven one-day and five twenty20 games for the province. His selection, though, is perhaps an indication Otago's depth is not quite where it needs to be.
Eathorne, who is overseas and could not be reached for comment, has a high score of 37 not out in all three formats and, with an average of 7.54 in first-class cricket, can count himself fortunate.
"It was one of those tricky ones where if you are not quite able to get a contract and commit full time to cricket you sort of get in a position where you have to look at other things,'' Otago winter squad manager Craig Cumming said.
"Sean had a bit of time away and then in the last year or two has certainly been a high performer in club cricket. He has done well for the Otago A side and got an opportunity for the Volts last year but broke his thumb in a first-class game and that curtailed his season, really.
"But he is a guy who we think can play well in the white-ball formats as well as be middle-order cover in the first-class side.
"We believe being able to commit full time to cricket will be a huge benefit to Sean and also to the team.''
Rae retains his contract. He has played six first-class game since making his debut in December, 2014.
Statistically, there is not much to fear. He has eight wickets at an average of 60.37 and a strike rate of 107.2 - that is in one wicket every 18 overs.
Cumming said the 21-year-old had time on his side and had been working on making the improvements necessary to compete at the top level.
"Last year was a big learning curve for him and I can tell you now he has been training exceptionally hard through the winter.''
Rae has been working on improving his release and produced some personal-bests in terms of his strength and conditioning. He is also very motivated having been aware of how close he came to missing out on a contract.
"It was maybe a wee scare for him and that sometimes makes you want to work harder. You find out about the character of a person and I've been delighted with the way he has responded.''
Otago Volts
Contracts
Warren Barnes, Michael Bracewell, Derek de Boorder, Jacob Duffy, Ryan Duffy, Sean Eathorne, Josh Finnie, Jack Hunter, Anaru Kitchen, Rhys Phillips, Michael Rae, Hamish Rutherford, Christi Viljoen, Sam Wells, Brad Wilson.
