Ulster will be able to register Schalk van der Merwe for their Heineken Champions Cup opener against Leicester Tigers on Saturday despite the South African not being originally listed for the competition.
The former Montpellier man arrived at Ulster in 2017 on a three-year deal but has featured only three times for the side since, all last season.
This season it has been Andy Warwick and youngster Eric O'Sullivan sharing minutes at loosehead, but the latter is in the process of undergoing the return to play protocols having sustained a concussion in the game against Connacht last Friday.
In his potential absence, Rodney Ah You, who can play both sides of the scrum, would likely have featured, but the former Connacht man may well see a ban for the red card he picked up for the A team last week.
That would leave Warwick as the only registered loosehead for Europe but Ulster coach Dan McFarland confirmed dispensation can be made.
"If we are left in a scenario on Thursday that we are without the requisite numbers we can bring him in," he said.
"We do not have to deregister someone in the front row, it is an emergency situation."
Ulster have been boosted by the return in s to training of Jordi Murphy, Will Addison, Craig Gilroy and Marty Moore ahead of the game.