Ireland winger Andrew Trimble will miss the last two matches in the Six Nations after breaking a bone in his hand.
The 32-year-old suffered the injury during Ulster's Pro12 win over Treviso in Belfast on Friday evening.
Tommy Bowe has been drafted into the Irish camp as they prepare to play Wales in Cardiff on Friday night.
Ireland must also do without Connacht lock Ultan Dillane, who will be sidelined for at least two months after undergoing shoulder surgery.
Head coach Schmidt will now hope to have stalwart full-back Rob Kearney back in full training on Monday.
Kearney had been battling a hip issue but is now thought to be ready to come back.
The British and Irish Lions full-back's return could offset Trimble's loss, with Ulster's Jared Payne then likely to go head-to-head with Garry Ringrose to start at outside centre in Wales.
Ireland are second in the Six Nations table, three points behind leaders England.
Schmidt's side lost to Scotland in their first match but then beat Italy and France.