After graduating from the Newcastle United youth system, Inman was sent out on developmental loan spells at Crewe Alexandria, Peterborough United and Rochdale. In 2018, he left the Toon for a permandent move to Rochdale, before joining Brisbane in 2019. During his years at Newcastle, he never played a competitive game for the NUFC first team. The only time he was included in the reserve bench was in January 2009 at a match against Manchester City.
With him joining the Mariners, the team's seven overseas players have now been signed. Inman will be placed alongside the likes of Carl McHugh, Javi Fernandez, Sk Sahil and Michael Regin to boost the club's mid-section.
He is also likely being brought in as a possible AFC-quota player as he has chosen to represent the Australian national team in senior football, and been an unused substitute in a friendly against England back in 2016. This means, if Aussie forward David Williams gets injured or is unavailable for some reason, Inman will replace him in the club's AFC Cup 2021 squad.