Joe Schmidt is "quietly confident" tighthead prop Mike Ross will be fit in time to ease Ireland's front-row injury crisis against South Africa.

Ireland boss Schmidt conceded it is a worry Ross has not featured in a month through groin trouble, but still backed the 34-year-old to cope against the Springboks next weekend.

Connacht tighthead Nathan White had been lined up for his Test debut against South Africa, but suffered biceps tendon damage in a training clash on Thursday.

Stephen Archer and Rodney Ah You are standing by to cover Ross from the bench, but the duo boast just three caps and no Test starts between them.

Schmidt lamented the "catch-22" of sending undercooked Archer, Ah You and further tightheads Declan Fitzpatrick and Tadhg Furlong into provincial action this weekend just a week away from facing the Springboks.

"If it was a perfect world things might different but you work in the world that's available to you" - Joe Schmidt

"Nathan White sustained some tendon damage in his biceps in an incredibly innocuous event, but a frustrating one for both him and us," said Schmidt of the Connacht prop now sidelined for 16 weeks.

"He just caught a player running past him, and it was just the angle, just the way it happened; it's just one of those things.

"Mike Ross is progressing pretty well, so we are quietly confident. He's taken part in some of the more static aspects of training. And he involves himself in some of the more static aspects of the game, so hopefully he comes through and can be involved in some of those.

"Absolutely it's a concern [that Ross has not played for a month]. But Mike has been working really hard, in his defence.

"There's nothing like game conditions though, to bring game awareness. You want guys to have had that; you want it to be second nature, what they are doing.

"If it was a perfect world things might different but you work in the world that's available to you, and I'd still say it's an incredibly exciting challenge to play one of the form teams in the world, and certainly one of the top-ranked."

Ireland will launch their three-Test series against South Africa at the Aviva Stadium on Saturday, 8 November, without at least 15 regulars missing through injury.

James Cronin will miss the entire series with ankle trouble, compounding loosehead prop resources and adding to Jack McGrath's workload with Cian Healy a long-term absentee.

Schmidt admitted he had to resist the temptation to pull the likes of Ah You and Archer out of club action this weekend, believing they must sharpen up ahead of potential Test action.

"Obviously Rodney Ah You is playing for Connacht against the Ospreys, and Stephen Archer will have some time at Munster," he said.

"Tadhg Furlong will play for Leinster and Declan Fitzpatrick for Ulster, those are our other options.

"It's a catch-22, because Nathan White was the starting prop at Connacht and has really dominated the starting time [and] Rodney needs the game time.

"Tadhg Furlong certainly needs to play; he's been sat behind Michael Bent.

"Declan Fitzpatrick has been massively underplayed because he's had a succession of injuries and Stephen Archer the same.

"So it's not a lot of rugby for those guys in the last two weeks to then have a week off and go into a Test match, it would be pretty difficult.

"So we're just going to hold our breath and hope that those guys come through okay and that we'll have some options live from that group."