The Scot signed for City last summer and it seems that Cardiff have not yet paid for him.
"The Board have been very patient with Cardiff given the financial pressures they have faced," said Motherwell chief executive Leeann Dempster.
"However the interests of our shareholders, employees and fans are being jeopardised by the failure of Cardiff City to pay the debt that they have outstanding.
"We have made clear to the Board of Cardiff that we are left with no option but to pursue every possible avenue of recourse to secure our own club's interests. We hope that this matter can be resolved in an orderly manner."
There has been no reponse yet from Cardiff City.
Chairman TG has been busy trying to right the financial mess he inheritted but it looks as if he can't get it done quick enough.
We've been late submitting accounts, late paying wages, late paying the taxman now late paying for transfer fees, other debts have been negotiated to equity.
Forgive if I'm mistaken but didn't Peter Ridsdale say before he left that we were the best shape we'd been in for ages? Excuse me!
The new season is just over two weeks away.