Ireland wary of loose forward conundrum
Easterby confirmed that flank could miss the sold-out Test match against South Africa on Saturday.
The Munster flank O'Donnell picked up an shoulder injury during training and is set to undergo a scan.
With No.8 Jack Conan and flank Dan Leavy already unavailable, O'Donnell's injury does limit the back row option.
However, the Britsh and Irish Lions combination of Peter O’Mahony, Sean O’Brien and South African born CJ Stander with Rhys Ruddock on the bench can still provide plenty potent to tackle the Springboks.
Speaking at a media session after training at Carton House, Simon Easterby said: "O'Donnell picked up a bit of a shoulder bump in training so he's due to have a scan.
"Conan sat out training, he just had a heavy workload, and Leavy had a bit of tightness in his hamstring, obviously he played at the weekend. Again it's just managing his workload.
"It's just about being sensible and earmarking players who may have potential weaknesses. If you know about things, at least you can prepare for that and not take any unnecessary risks,"
