Republic of Ireland international Hendrick has found his first-team opportunities at St. James' Park limited since the arrival of Eddie Howe last November, and spent the second half of last term on loan with Queens Park Rangers, where he made ten appearances in the Championship.
And he has now made a similar move to the Select Car Leasing Stadium to link up with Reading, who are managed by former England midfielder Paul Ince.
Hendrick, 30, has made 27 appearances for Newcastle since joining the club from Burnley in August 2020, scoring three times.