Ulster prop Declan Fitzgerald suffered an irregular heartbeat during Friday's 27-9 loss to Glasgow Warriors at Scotstoun.
Fitzgerald underwent a successful procedure on Sunday to correct the irregularity. He left hospital on Monday and will return to Belfast where he will undergo further tests.
Elsewhere, Ricky Lutton sustained an injury to his toe in the game against Glasgow. An x-ray on Monday showed that there was no break. He will have ongoing physiotherapy ahead of the Leinster game next weekend.
Tom Court suffered a thumb injury on Friday. An x-ray on Monday showed that it was not broken and he will resume training later this week.