Australian lock forward Alex Toolis has joined London Irish from Edinburgh Rugby on a short-term loan deal.
The 22-year-old, who had a loan spell with the Exiles last season, joins as cover for Nic Rouse and Sean Cox, who are both out with injuries.
"We have a few injuries in the second row so Alex has come in to add a bit more depth to that position," London Irish director of rugby Brian Smith told the club's official website.
"He did a good job for us last season when he played in the LV=Cup and I have no doubt he will do well again when he gets his chance."
London Irish resume their Aviva Premiership season with a trip to Exeter Chiefs on Saturday.