Moller travelled to Melbourne on Friday morning as an emergency for the match against St Kilda at Etihad Stadium this Saturday.
The 19-year-old joined Fremantle as an add-on rookie at pick 47 in the 2012 Rookie Draft after three seasons linked to the club through the NSW AFL scholarship program.
Fremantle selected Howson, a 195cm forward from East Fremantle, with pick number 25 in the 2012 Rookie Draft.
