Middlesex have taken legal advice in a bid to make captain Leus du Plooy available for the rest of the season after an embarrassing administrative error inadvertently jeopardised his status as a local player.

Du Plooy, 31, has played as a local player in county cricket since 2019 thanks to his Hungarian passport. He had previously expressed his desire to play for England but recently informed the club that he intends to recommit to his native South Africa. He will be eligible to play for them immediately under ICC regulations and will join Titans for the upcoming domestic season.

Du Plooy was under contract with Middlesex for 2027, but the club announced on Saturday morning that he would leave them at the end of this summer after his decision to recommit to South Africa, which would have forced them to re-register him as an overseas player for the final year of his deal and had the potential to limit his availability.

However, Middlesex were unaware until Monday morning that, under ECB regulations, du Plooy’s declaration automatically rendered him ineligible to continue playing as a local player for the rest of the county season. While they had a vacant spot in their squad for an overseas player, they did not realise their mistake until after Sunday’s deadline to register one.

The ECB’s ruling means that du Plooy will not be available to play in next Sunday’s Metro Bank Cup final – Middlesex’s first List A final since 1990 – against Leicestershire at Trent Bridge. He has not featured in the competition this season due to his involvement in the Hundred, though would have been eligible but for Middlesex’s error.

Du Plooy travelled to Chester-le-Street on Monday as the club sought a resolution with the ECB but was left out of their playing XI to face Durham in the County Championship, with Max Holden replacing him as captain. Middlesex sit fourth in Division Two but their promotion hopes are slim, even after bowling Durham out for 252 on Tuesday.

Alan Coleman, Middlesex’s director of cricket, said that the club had sought legal advice and were working with the Professional Cricketers’ Association in an attempt to overturn the ECB’s decision on du Plooy’s availability. “We will continue to position this and discuss this with the ECB and hope for a positive resolution,” he said.

Coleman described the situation as “really disappointing” and suggested that the club disputed the ECB’s interpretation of the situation. “This is a regulation around Leus’s right to work as a local player in cricket, and links to the affidavit that he signed back in 2019 [declaring his intention to qualify for England] when he joined Derbyshire,” he said.

“The confusion sits around the word ‘intention’. Leus intends to go back and play for South Africa, or to make himself available to play for South Africa. We believe that meant he could play until the end of the season, but in the ECB’s eyes, that intention starts the moment they learn of it.”

This is the second time this season that Middlesex have had a contracted player unavailable due to registration issues, after New Zealand’s Matt Boyle missed the first half of the T20 Blast. Coleman denied that his recent decision to step down from his role was linked to du Plooy’s situation: “There’s no correlation between them at all.”

Meanwhile, Titans do not expect to have du Plooy available until their second match of the South African domestic season at the earliest. The provisional side’s CEO Jacques Faul confirmed to Cricinfo that they had initially expected to sign him as an overseas player from the end of the Championship season onwards, but they will now sign him as a local instead on an all-format deal.

Cricinfo has also confirmed that du Plooy only needs to “pitch up and play”, in the words of one CSA source, to be available for international selection, and that he is being seriously considered by South Africa’s selectors. He is believed to have impressed Albie Morkel during his time at Joburg Super Kings in the SA20, who has since worked as a white-ball consultant for the national side.