2009 season:
Sellar gained another opportunity in round 14 against Richmond after an injury to Brad Moran. He retained his spot in the side for the remainder of 2009 and showed a lot of promise. He shared the ruck duties with Ivan Maric and his competitiveness in the ruck and around the ground was very encouraging. He had 94 disposals and 94 hitouts in 11 games and after a disappointing year in 2008, which included his AFL debut, Sellar was determined to put in the extra work to get his opportunity. "We'd train for three-and-a-half hours (during pre-season) and then I'd come in and work really closely with Charlie Walsh for another hour-and-a-half,” Sellar said. “I was also doing extra skills and extra marking sessions because I really wanted to have no excuses and no regrets. The coaches wanted to see constant improvement and I wanted to show them that I was a player hell-bent on making it in the AFL and that it was really important to me." "I'm still just 20 years old and I think people sometimes forget that, but I'm working as hard as I can, I'm developing, I'm learning and I'm really excited about the year ahead."

David Noble’s 2009 review:
“The penny has dropped for James. He added to our team in a way that we wouldn’t have expected. Everyone had seen him more as a forward, but to his credit he was able to stand up in the ruck under all sorts of scrutiny when we needed him. The real telling moment was the incident in the elimination final against Essendon. James showed real desperation to get hold of the ball and was almost knocked out in the process, but he was able to come back on and perform under duress. That could be a defining moment of his career and development.”

Career:
Sellar won the Kevin Sheehan Medal at the 2005 national under 16 championships and played international rules for Australia U17 against Ireland. Sellar chose football ahead of a volleyball career. He captained South Australia's under-17 volleyball team at the 2005 national championships, got picked in the All-Australian team and was treated like a movie star when he travelled to Taiwan with the national under-19 side for the world youth championships. He showed promise in the 2008 pre-season kicking three goals against Collingwood in Dubai before making his debut in round seven against North Melbourne. He struggled for form in the SANFL but showed glimpses of his promising talent in Glenelg’s reserves.