A final call on Ulster's Kingspan Stadium pitch is likely to come this afternoon.
Work went on through the night to maintain hope that tomorrow evening's Heineken Champions Cup clash with La Rochelle can go ahead.
Ulster say contingency plans are in place if the game cannot be played in Belfast.
Leinster will look to register back-to-back pool wins in the Heineken Champions Cup tonight.
Garry Ringrose once again captains the side, with Gloucester visiting the RDS.
Kick-off there is at 8.
Bundee Aki is back in the Connacht centre for their Challenge Cup game away to Brive (pr: Breev).
There's also an 8 o'clock start to that one.