It is understood Trout's post was scrapped to cut costs. He took over from Tim Bleakley as managing director last November, after three years at the company.
Ashley MacKenzie will take on responsibility for Impact in addition to his existing role as managing director of TWG's Independent Local Radio division.
No one at the Wireless Group was available for comment as Marketing went to press. However, industry observers were baffled by Trout's departure.
One source said: "I don't know any sales force that doesn't have a sales director. A lot of what talkSPORT has achieved has been on the back of relationships that Jason maintained. In heading up a national sales team, dealing with agencies and relationships are key."
TWG's revenues were up 6.7% in the six months to June, compared with a 3% drop in the industry's ad revenues.