CIARA Mageean and Rhasidat Adeleke have both been forced to withdraw from this weekend's National Track & Field Championships at Morton Stadium in Santry.
Portaferry's Mageean, who last week shattered Sonia O'Sullivan's 29-year Irish mile record, has been stood down as a precautionary measure.
A statement released described her injury as "a niggle" and Mageean will be turning her thoughts to the World Athletics Championships commencing in Budapest in three weeks' time, where she will be a strong medal contender in the 1500m.
Promising youngsters Sophie O'Sullivan and Sarah Healy, a Tokyo Olympian, will take centre stage in Mageean's absence.
Adeleke, who was due to compete in the heats of the 200m on Saturday afternoon, withdrew on medical advice.
Her absence will make the event a wide-open contest with Lauren Roy (City of Lisburn AC) now ranked as the likely favourite based on her season’s best of 23.54.
Limerick sprinter Sarah Lavin aims for her eighth national outdoor title, with Olympic qualification already secured.
She will partake in the 100m hurdles final on Saturday, as well as the flat equivalent on Sunday.