Devin Toner is likely to miss out of the Ireland Rugby World Cup squad which Joe Schmidt will submit today.
Kleyn made his Ireland debut in the warm-up game against Italy last month. He had only become eligible under residency rules days earlier.
Considering the awful performance of the Ireland lineout during the heavy defeat to England at Twickenham last month, it is a major surprise that Toner is unlikely to make the trip to Japan.
Under Schmidt, he has been Ireland's most reliable lineout option and caller. It had been presumed the return of Toner, along with his Leinster teammate James Ryan to the starting team, would settle the Irish set piece.
Toner, who has 67 caps for Ireland, came off the bench in the win against Wales at the weekend.
Other notable names set to miss out include Connacht scrum-half Kieran Marmion with Schmidt taking Luke McGrath as Conor Murray's only backup, and Ulster backrow Jordi Murphy. Leinster's Rhys Ruddock is likely to be included instead. Munster forward Tadhg Beirne should also make the squad.
Jack Carty and Joey Carbery will be Johnny Sexton's understudies at out-half.
Though Schmidt must submit his squad to World Rugby today, he will not officially announce his squad until Sunday, a day after Ireland's final warm-up game against Wales in Dublin.
Ireland's opening game of the World Cup is against Scotland on September 22nd.
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