On paper, the decision he and his partner, Russ Lidstone, took to side with the Euro RSCG Worldwide chief executive, David Jones, and take up residence with Euro RSCG London (page 1) seems the least likely scenario.
After all, only a year into his tenure at JWT London, he clearly still had more to prove to Sir Martin Sorrell. And offers such as Sir Frank Lowe's - a start-up agency that, when it finally opens its doors, will start trading with profits of £5 million - do not come along more than once in a career.
Cadman and Lidstone will have their work cut out for them at Euro RSCG; the agency has been virtually rudderless since the departure last year of Ben Langdon and its thinning roster of accounts desperately needs addressing.
In addition, the pair will need to demonstrate a long-term commitment to Jones if Cadman is to stop tongues wagging about his perceived reluctance to stay at an agency for the long haul.