Leinster’s monopoly of the Ireland number one jersey is under threat.

Cian Healy’s hamstring tear is comparable to that suffered by Richardt Strauss, who has been out since last May, putting his availability in doubt for the autumn internationals.

Ireland face the Springboks at the Aviva stadium on November 8th, Georgia on the 16th and Australia on the 22nd.

Healy, 27 next month, played only 23 games last season, which included all eight Ireland matches due to his latest ankle surgery.

His understudy, Jack McGrath has a calf problem that may clear up in time for Munster’s visit to Dublin on October 4th.

Munster pair James Cronin and Dave Kilcoyne are the next in line for test recognition should Healy and McGrath be ruled out.

Healy’s remarkable powers of recovery must be taken into consideration. Capped 47 times for Ireland since 2009, he wore a moon boot on his ankle after most games last season and his training schedule is akin to a veteran prop.

Michael Bent, the tighthead convert, starts against Cardiff tomorrow (kick-off 7.35pm), with Ed Byrne, the highly rated former Clongowes Wood prop, joining twin brother Bryan among the replacements.

Marty Moore will make his first start of the season at tighthead.

Injuries to Seán O’Brien (ankle) and Shane Jennings (hamstring) mean Jack Conan covers the backrow of Rhys Ruddock, Dominic Ryan and captain Jamie Heaslip.

Zane Kirchner is also out with a hamstring injury.

O’Brien, who had shoulder surgery last December, underwent ankle surgery last week and is another doubt for Ireland’s November campaign.

Coach Matt O’Connor has also named new recruit Kane Douglas to start against the Blues.

The Australian lock, who comes from New South Wales Waratahs, where former Leinster coach Michael Cheika is in charge, arrived in Ireland last Friday and participated in training this week with his new team-mates. He lines out beside Ireland’s Devin Toner, who makes his third start of the season.

O’Connor has also gone with Gordon D’Arcy at outside centre with Ian Madigan inside him. It’s a first start this season for the Irish inside centre, D’Arcy, and will surely invite opinion on where his role will be over the coming months.

Leinster: R Kearney; F McFadden, G D’Arcy, I Madigan, D Fanning; J Gopperth, E Reddan; M Bent, S Cronin, M Moore, D Toner, K Douglas, R Ruddock, D Ryan, J Heaslip (captain). Replacements - B Byrne, E Byrne, T Furlong, M McCarthy, J Conan, L McGrath, S Crosbie, M McGrath