Guy Armitage has cut short his spell at Toulon to rejoin London Irish as emergency midfield cover.
The Exiles have lost Joe Ansbro to a broken neck while the arrival of new signing Setaimata Sa has been delayed, leaving them short of centres.
Winger Sailosi Tagicakibau has been filling in at 12 with limited success, so Armitage - who followed brothers Steffon and Delon, both England internationals, from Irish to Toulon - has returned to the Madejski Stadium until the end of the season.
"I was very keen for Guy to stay on at the club so I'm delighted he has rejoined us for the season," director of rugby Brian Smith said.
"Guy's development at Toulon was always going to be in stages and it makes sense in season one to come back for first-team game time and continue his development."