Jonathan Reynolds is being linked with a senior business post in the Labour leader's new team which will be announced in the next few days.
He had previously quit the role of Shadow Minister for Transport in January in response to what was dubbed the "revenge reshuffle".
It came after Jeremy Corbyn sacked Pat McFadden from the shadow Europe minister brief over "disloyalty", after he appeared to criticise his stance on terrorism.
Now Reynolds is poised to take the shadow city minister role, telling Premier Brexit had changed his views.
"This is going to be the biggest thing the UK has had to find a way through for some time in British history," he said.
"Frankly I feel that if Labour isn't an effective opposition, isn't holding the government to account, then frankly I feel people will be very angry about that".
On Premier's News Hour he explained how the group he chairs, Christians on the Left, should be used better by the Labour party: "I think we've got a lot to offer and i think Labour has to reach out a lot more to Christians, I've said that quite a few times.
"We talk a lot about the impact of austerity on communities but I see churches providing a lot of the response to that in terms of foodbanks and working with the homeless and we've got to talk to those people."
He said Jeremy Corbyn had to now "speak to the country" after beating Owen Smith in a leadership contest.
"He's going to have to address the lack of unity that's been in the party and I think he's going to have to say we're not going to achieve anything unless we come together," he added. "In terms of where he goes next, he's now got to convince the country".
Meanwhile Corbyn has given his keynote speech to the party's conference.
Increased borrowing to fund better railways, broadband, housing and other infrastructure projects will show Britain has not "given up", he said.
Corbyn insisted in his keynote speech to his party's conference it would be "foolish" not to borrow to invest at "historically low interest rates", claiming this will generate "far greater" returns.
Jonathan Reynolds speaking to Premier's Marcus Jones:
