Ulster Rugby have pulled out of signing Arno Botha.
The Springbok forward was set to join the province this summer on a two year deal from his current club Blue Bulls.
However, injury problems have led Ulster to revoke their contract offer, deeming the transfer too big a risk. They will announce an alternative forward-line signing "in due course."
Botha picked up a knee injury in New Zealand last month and, although he is set to return to action this weekend, Ulster obtained an independent medical opinion as part of 'meticulous processes' for player recruitment.
"It's unfortunate for both Arno and Ulster Rugby that we've had to come to this decision as we were looking forward to welcoming him to Kingspan Stadium. However, we have acted with the best interests of team performance in mind," said Ulster Operations Director Bryn Cunningham.
"We have meticulous processes in place for all player recruitment and having commissioned an independent medical assessment in South Africa, it was recommended that the risk had increased following his most recent injury. This view was shared by our own medical team.
"Everyone associated with Ulster Rugby sincerely hopes that Arno will go on to have a long and successful career.
"Once this decision was reached, we compiled an extensive list of potential targets and we will announce a signing to bolster the forward pack in due course.”
The 25 year-old's latest injury adds to previous torn knee ligaments that led to a lengthy spell on the sidelines.
Speaking in January, when Ulster initially announced the signing, Ulster coach Les Kiss had hoped Botha's injuries worries were a thing of the past.
"Arno was tipped to be a future Springboks captain from a young age but his career was somewhat curtailed by injuries after he made his international debut in 2013. Those injuries are behind him now and he has regained his best form over the past 12 months," he said.
Ulster, of course, have signed Connacht's John Cooney for next season. The scrum half was earlier this week included in the Ireland squad for the summer tour to New Zealand and Japan.