Ireland could have to look to their fourth choice tight-head against South Africa as Nathan White will miss the autumn Test series.
The Connacht tight-head ruptured a tendon in his upper arm in training with Mike Ross struggling with injury and Marty Moore definitely out of the picture.
The New Zealand-born anchor faces surgery next week and could now be sidelined for as long as four months.
The 33-year-old was lined up for his international debut against South Arica next weekend. His absence further drains Ireland's already stretched front-row resources.
The former Leinster front-rower had been expected to understudy Mike Ross across the autumn series, with Marty Moore already out for three months after shoulder surgery.
Now head coach Schmidt and Ireland will be pin his hopes to Ross, even though he is not a racing certainty to make it.
The 34-year-old scrum cornerstone Ross is scheduled to return to full training next week.
But groin injuries are notoriously tricky for front row forwards. The big-scrummaging Springboks would have looked to take on Ireland's set-piece even if the Aviva Stadium hosts were at full strength up front next weekend.
White's absence, allied to Moore's shoulder surgery and Ross's problem leaves Ireland short of experience at tight-head for the South Africa clash.
Schmidt had admitted he promoted White into the squad for his potential debut on the strength of his lengthy top-level club career, expecting the 33-year-old to handle Test intensity better than several promising but young and raw prospects.
Now the former Leinster coach must draw on Connacht's versatile front-rower Rodney Ah You and Munster's Stephen Archer as potential starters.
Schmidt should be able to call on Jack McGrath at loose-head as he aims to step up his return from injury, offsetting Cian Healy's long-term absence.
Ireland will still be shorn of at least 15 stars for the visit of Heyneke Meyer's Springboks before entertaining Georgia and then Australia across the three-Test Guinness series.