The Central District player, who has had a promising season at SANFL level, caught the attention of clubs and was one of 98 players on the combine's original list.
But after some time spent considering his options, Glenn has turned down the chance to test at the weeklong event at Etihad Stadium.
His club will encourage him to take part in South Australia's state screening a week or so after the national combine.
It is understood Glenn, a 180cm medium defender, is yet to decide if he wants to pursue an AFL career and had concerns about leaving Adelaide.
The 19-year-old's best game of Central's season came in round seven, with 35 possessions and 13 marks against Sturt.
His reluctance follows that of Central District's defender Paul Marschall last year, who did not nominate for the 2012 NAB AFL Draft despite interest from clubs.
The national combine takes place between October 1-4.
Twitter: @AFL_CalTwomey
