The Taieri fullback made a huge impact for the Eels three years ago as a rookie first five-eighth.
Whether he was carving his way through traffic or slotting goals, Casey was almost always part of the scoring action.
He became the first player to score 300 points in a season since the Otago Daily Times started keeping detailed records in 1976.
He was filling in for regular pivot Hayden Parker, who was injured that season, but his success opened up possibilities.
He got a playing gig in Spain at the end of the campaign and headed over hoping to develop his game at first five-eighth.
But when he returned midway through the 2016 season, Casey had transformed.
He was sporting a more robust frame and had adopted a mechanical playing style. His left ankle was a constant source of pain as well.
That burst of speed and quick feet were not always evident, and he spent a good chunk of 2017 on the sideline before getting corrective surgery.
He spent the summer in Twizel recovering and getting himself back into prime physical condition.
"I would have been 88 or 89kg when I came back from Spain," Casey said.
"Now I'm back down to 82kg and I just feel fast, far more mobile and agile. Once my ankle came right over the summer I put a big emphasis on fitness and got into running and biking."
Arguably he is the form player in the competition. The 24-year-old has scored seven tries in the past three games and is the tournament's leading scorer with 150 points.
He is rebranding himself as an attacking fullback who can kick goals and fill in at first five-eighth.
North Otago is certainly interested. It has contacted Casey but he is keeping his options open, although he is unlikely to chase another overseas playing role at this stage.
"I wouldn't mind having a full season as a fullback who can cover first-five and wing and try to crack it here in New Zealand with that tag rather than being just an out-and-out first-five.
"That is the goal going forward now."
Casey will put that ambition on hold this weekend. He suffered a head knock during the 44-42 loss to Southern on Saturday and has been ruled out for the crucial match against Harbour at Peter Johnstone Park tomorrow.
"We have not tasted back-to-back defeats this year so we want to bounce back straight away.
"But with the way Harbour have been playing, it is going to be bloody tough."