The raft of international players joining English counties from South Africa is set to continue with Glamorgan close to signing the 26-year-old fast bowler Marchant de Lange on a long-term deal, despite him not qualifying under the controversial Kolpak ruling.

Seven recent internationals have joined counties as Kolpaks in the close season, but De Lange is not eligible to play as one because he has played an insufficient amount of international cricket in the past two years. Kolpak registrations require the player to have appeared in one Test match or 15 limited-overs internationals in the 24 months before signing. In that period, De Lange has played one ODI and one T20 international.

Instead, pending the awarding of a visa and ECB approval, he will be registered as a local player as his wife has a British passport.

The ramifications of this are more severe than for a Kolpak registration. While, like a Kolpak, he would be ending his South Africa career to make the move, he would only be eligible to play as a local player in one country’s domestic competitions. Thus, if he wants to continue playing South African domestic cricket, it would have to be as an overseas player.

De Lange and his agent, Weber van Wyk, have informed the player’s franchise, the Bloemfontein-based Knights, of his intention and the two parties are in talks over his return as an overseas player next summer.

Van Wyk has already sealed Kolpak registrations for Rilee Rossouw and Kyle Abbott at Hampshire, David Wiese at Sussex, Dane Vilas at Lancashire and Hardus Viljoen at Derbyshire since the end of last summer. As well as these five, Stiaan van Zyl has joined Sussex and Simon Harmer will play for Essex, while the uncapped 25-year-old Colin Ackermann is registered as a local for Leicestershire.

De Lange, a tall fast bowler with genuine pace, took seven for 81 in his first Test innings against Sri Lanka in 2011, but he has played one more match since. In addition, he has played four ODIs and six T20s. This season in South Africa he has taken 35 wickets at 28 in nine first-class matches, as well as 19 wickets in 11 white-ball games. He will join a Glamorgan squad led by the former Protea batsman Jacques Rudolph, who is the overseas player (although Glamorgan had originally tried to sign him as a Kolpak), and containing South Africans Colin Ingram, who is a Kolpak, and Chris Cooke, who has a UK passport.

Cricket South Africa told the Guardian in December that they were powerless to prevent players leaving for county deals that render them unavailable for international cricket, but they are understood to be assessing how best to deal with returning Kolpaks. One option is to limit the number playing in each team in their own domestic competitions.

One of the reasons for the recent rush of Kolpaks – alongside the weakness of the rand – is the unknown impact of Brexit on the ruling. However, De Lange’s departure is expected to be the last of South Africa’s talent drain to county cricket before the new season, which begins on 7 April, although representatives of the off-spinner Dane Piedt confirmed to the Guardian that he remains open to offers.