The Lions have reached a "verbal agreement" with Clarke but are yet to get the contract in ink.

GGGM coach Jayden Kotzur says all that is left to complete the deal is a few small formalities.

"I can't see anything going wrong with it but we just haven't put pen to paper yet," Kotzur said.

"Matt has basically committed to playing for us, we've shaken hands and he has told me he will definitely play with us next year."

Kotzur said Clarke will sign on before GGGM begins training in three week's time, but is itching to seal the deal as soon as possible.

Clarke will leave Osborne to join the Lions and will be a big get, having been considered one of the best midfielders in the Hume League for a long time.

He spent a season with East Wagga-Kooringal in the Farrer League two years ago before returning home to the Cats to win a premiership in 2012.

Clarke will be the first significant signing for GGGM as the RFL has gone into an off-season slumber.

The Lions have only confirmed the one loss in Scott Crozier to date.

Kotzur is in talks with "four or five blokes" and is hopeful of securing more signings in the coming weeks.