They say the player didn't travel to take on Scarlets last weekend.
Munster Rugby have suspended all training, 'as a precautionary measure', due to a new positive Covid-19 case in their senior squad.
The province say the senior player is asymptomatic and didn't travel for the clash with Scarlets in Wales last weekend.
Six other players identified by Munster as potential close contacts are currently self-isolating.
The HSE has also been notified for contract tracing purposes.
Wales rugby union head coach Wayne Pivac has called up seven uncapped players in his squad for the autumn internationals.
Among those are centre Johnny Williams and fly-half Callum Sheedy - both of whom are eligible for England.