The veteran prop, 34, has made seven appearances this season for FC. He has a wealth of experience behind him, having won the Challenge Cup four times, and played 220 Super League games in his career.
“Garreth is a very experienced front rower who will complement and strengthen our options during a critical point of the season,” said Tigers head coach Daryl Powell.
“His experience as a tough international prop with real size and ability to break the defensive line is outstanding. I have worked with him before and I am confident he will fit into our system with ease.”