London Irish hooker David Paice has been ruled out for up to two months after suffering a broken arm in last weekend's game with Leicester Tigers.
The 30-year-old was injured in the first half of the 20-11 defeat at Welford Road and had surgery on Monday.
"David had surgery on a pretty bad break so he will be a month or two out of action," director of rugby Brian Smith told BBC Radio Berkshire.
Smith confirmed they would now look to try and bring someone in on loan.
Meanwhile, the Exiles have added renowned scrum 'doctor' Phil Keith-Roach to their staff after repeatedly being penalised up front and struggling to win ball this season.
Keith-Roach was the scrum coach to the England 2003 Rugby World Cup-winning side and Smith, who has know him for 30, hopes his expertise will help out his forward unit.
"There is no one on the planet who knows more about scrummaging than Phil Keith-Roach, so he has come in and is working with us and is someone I would like to continue working with," said Smith.
"We have to put whatever resources we can into the problem as it is holding us back as a group. We want to be pro-active and do something about it.
"My firm belief is, it is 80% perception how we are being refereed at the moment, but is up to us to turn this around.
"Phil is coming in for the rest of the season and potentially beyond. He will work on small technical things with each player one to eight. He has looked at every one of our scrums this season, that is what he does."
Exiles lock George Skivington also hopes Keith-Roach can help the side find their edge in the scrum.
"There a couple of things we need to sort out and we perhaps need to be a bit more street wise," he added.
"He's given some really good tips, but it'll take practice and in the long run it will be a great thing for us,"