Premiership champions Northampton Saints have given forward Jonathan Fisher a full-time contract.
Fisher, 25, impressed on trial, playing in three Saints pre-season friendlies as cover for the injured Sam Dickinson.
The former London Irish back-row was a member of the England Under-20 team which reached the 2008 Junior World Championship final.
Fisher was released by the Exiles in the summer after missing most of last season with a serious concussion.
"Jon is a talented player who will give us depth across the back row," said director of rugby Jim Mallinder.