Jonathan Sexton remains sidelined for Leinster's Rainbow Cup meeting with Connacht at the Sportsground.
The Ireland captain has been absent for nearly a month, having sustained his latest head injury in the Heineken Champions Cup quarter-final win over Exeter Chiefs.
Meanwhile, Rhys Ruddock will miss up to six-weeks with a calf injury.
The head injury suffered by Sexton in the first half at Sandy Park was his third in a short space of time.
The first came during Ireland's Six Nations defeat to Wales in February. Sexton missed the following week's meeting with France, but returned for the games with Italy and England.
His second head injury came during a substitute appearance in the Guinness PRO14 final win over Munster.
He'd been pictured training ahead of last week's Champions Cup defeat to La Rochelle, but was not involved in the travelling party to France.
Leinster head coach Leo Cullen was remaining patient with his experienced captain, saying, "We’ve had some experience with guys in and around concussion and Johnny is very much the same, just do what’s best by him really is the most important piece,” he said.
“Getting him seen by the best people out there and make the appropriate decisions on the back of that, he’s come through reasonably well."
However, Sexton's continued absence will be a concern for Lions head coach Warren Gatland. The Kiwi names his squad for the tour of South Africa on Thursday (May 7).
Ruddock looks set to miss the remainder of Leinster's season, having picked up a calf injury in the La Rochelle loss. The province expect the back-row forward to miss between four and six weeks.
Caelan Doris remains a doubt for Saturday's game in Galway with a calf issue of his own.
Jamison Gibson-Park is also having a hamstring injury assessed ahead of the trip out west.
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